The justices agreed they will hear the case after a therapist from Colorado brought an appeal, arguing the state’s restictions violate her free speech rights guaranteed under the US Constitution’s first amendment.

Conversion therapy – denounced by professional and health associations globally but promoted by some religious conservatives – aims to encourage lesbian, gay and transgender people to change their sexual orientation or gender identity.

The highest court in the US previously turned away opportunities to rule on conversion therapy bans.

More than 20 US states have banned conversion therapy for minors.

Kaley Chiles, a licensed counsellor and practicing Christian in Colorado Springs, Colorado, claims the ban in her state interferes with her ability to treat individuals with “same-sex attractions or gender identity confusion” who “prioritise their faith above their feelings”.

Ms Chiles, who is represented by the Alliance Defending Freedom, a conservative Christian advocacy group, has said some of her patients seek out her counselling to resolve internal conflicts about their sexuality or gender identity.

Colorado officials, however, have said the law does not regulate speech, it regulates conduct.

They said if the courts side with Ms Chiles, it would “undercut states’ longstanding ability to protect patients and clients from harmful professional conduct”.

“A professional’s treatment of her patients and clients is fundamentally different, for First Amendment purposes, from laypersons’ interactions with each other,” Colorado officials said.

Ms Chiles sued over the Colorado law in 2022 and multiple lower level courts denied her request to pause the enforcement of the law.

Last year, she appealed to the Supreme Court.

A similar case, brought to the Supreme Court in 2023, was rejected but three of the court’s conservative justices indicated they would have considered the case.

Justice Samuel Alito said in his dissent that “it is beyond dispute that these laws restrict speech, and all restrictions on speech merit careful scrutiny”.

The Supreme Court will hear the case during their next term, set to begin in October.

More than 1,300 practitioners across the US offer conversion therapy, according to a 2023 Trevor Project report.

Critics of conversion therapy say it can be emotionally harmful, cause mental health issues and increase risk of suicide. Some practitioners rely on talk therapy or prayer, but extreme cases have subjected patients to physical violence and food deprivation.

The American Medical Association rejects the idea that same-sex attraction or nonconforming gender identity are mental disorders, saying it is not supported by medical evidence.

On Wednesday, the top court upheld a lower court ruling ordering the administration to release the funds to contractors and grant recipients of the US Agency for International Development and the State Department.

Since taking office, President Donald Trump has cut numerous aid programmes and placed most USAID staff on leave or dismissed them.

Aid agencies argue these actions have jeopardised life-saving operations worldwide.

Last month District Judge Amir Ali had ordered the State Department and USAID to pay the bills to contractors for the work already done by midnight on 26 February.

As the deadline approached, the Trump administration sought an emergency relief from the Supreme Court, arguing it was impossible to process claims in an orderly fashion in such a short period of time.

Supreme Court Chief Justice John Roberts issued a brief administrative stay, before the full court acted on President Trump’s request.

On Wednesday, the top court in a narrow 5-4 decision declined to halt the lower court order that required the Trump administration to unfreeze the payments.

The court said that Judge Ali’s deadline for the immediate payment had now passed, and the district court should “clarify what obligations” the administration must fulfil to comply the order.

Conservative Justices Samuel Alito, Clarence Thomas, Neil Gorsuch and Brett Kavanaugh dissented with the order.

“Does a single district-court judge who likely lacks jurisdiction have the unchecked power to compel the government of the United States to pay out (and probably lose forever) 2 billion taxpayer dollars?” Justice Alito wrote in a dissent joined by the three other conservative justices. “The answer to that question should be an emphatic ‘No,’ but a majority of this Court apparently thinks otherwise. I am stunned.”

The case was launched by two aid groups who went to court last month to challenge Trump’s 90-day pause on foreign assistance.

Federal Judge Amir Ali in the District of Columbia then issued a temporary pause on the cuts while he examined the arguments in the case.

The aid groups later argued that the government had failed to comply with the pause, forcing the federal judge to issue another order requiring them to at least pay for work that has already been completed.

Proceedings in the case will continue, and the district court is set to hold a hearing on the contractors’ request for longer relief on Thursday.

The Trump administration is seeking to shrink the federal workforce and cut costs in a drive led by tech billionaire Elon Musk.

The cutbacks to USAID have already upended the global aid system.

Hundreds of programmes have been frozen in countries around the world since the president announced his intentions in January.

The US is by far the biggest single provider of humanitarian aid around the world.

It has bases in more than 60 countries and works in dozens of others, with much of its work carried out by its contractors.

In the long-running lawsuit, Mexico’s government argues that the “flood” of illegal guns across the border is a result of “deliberate” practices by US firms.

The gun industry’s trade association has denied any wrongdoing and blamed Mexico’s government for failing to control crime.

The flow of guns from the US to Mexico has recently emerged as a bargaining chip in talks over the implementation of tariffs on Mexican goods entering the US.

During oral arguments on Tuesday, liberal and conservative justices alike expressed scepticism about Mexico’s claims that US guns contribute to criminal networks.

“What you don’t have is particular dealers, right?” liberal Justice Elena Kagan told the lawyer representing Mexico. “Who are they aiding and abetting in this complaint?”

The lawsuit, which was first filed in 2021 in a federal courthouse in Massachusetts – where several of the companies are based – argued that the manufacturers knew that guns were being sold to traffickers fuelling violence in the country.

It has since become the focus of years of legal wrangling and appeals.

According to Mexican authorities, tens of thousands of US-manufactured guns are trafficking south across the border each year and into the hands of drug cartels, which use them to fight each other and the Mexican government alike.

Some estimates put the total at over half a million weapons each year.

The gun manufacturers, along with support groups such as the National Rifle Association (NRA), have argued that they are legally protected and that a lawsuit would undermine gun rights for Americans.

“Mexico has extinguished its constitutional arms rights and now seeks to extinguish America’s,” the NRA wrote in a legal brief filed to the Supreme Court. “To that end, Mexico aims to destroy the American firearms industry financially.”

At the heart of the gun manufacturers case is a federal law known as the Protection of Lawful Commerce in Arms Act, or PLCAA.

The law, enacted in 2005, is designed to protect gun companies from being held liable for the misuse of their weapons by criminals. The Supreme Court case marks the first time the highest court in the US will consider the law.

In court on Tuesday, liberal Justice Ketanji Brown Jackson said she thought it was likely the PLCAA means that “we don’t want the courts to be the ones to be crafting remedies that amount to regulation on this industry”.

The Mexican lawsuit also suggests that some weapons are being manufactured and decorated specifically to the tastes of cartel members – such as a gold-plated gold pistol known as the “Super El Jefe”, Spanish for “the boss”.

“Those are all things that are not illegal in any way,” conservative Justice Brett Kavanaugh said of the argument. “There are some people who want the experience of shooting a particular type of gun because they find it more enjoyable than using a BB gun.”

Kavanaugh also expressed concerns that penalising companies for the misuse of their products could ultimately impact other industries, such as pharmaceuticals.

The issue of US weapons in Mexico recently emerged as part of last-minute diplomatic manoeuvring over US President Donald Trump’s threats to impose 25% tariffs on goods coming from Mexico.

As part of a last-minute deal to avoid the tariffs coming into effect on 3 February, Mexican President Claudia Sheinbaum said the US had agreed to increase measures to prevent the trafficking of high-powered US weapons into Mexico.

On 14 February, however, Sheinbaum warned that the lawsuit against manufacturers could be expanded if the US designated Mexican cartels as foreign terrorist organisations – a move the administration took just days later.

Trump’s tariffs on goods from Mexico – and from Canada and China – ultimately came into effect on 4 March.

At least 25,000 people were murdered last year in Mexico, which has extremely restrictive gun laws. The country is home to only one gun shop, housed in a Mexico City military complex.

Statistics from the US Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) show that between 2017 and 2022, nearly half of all weapons recovered from crime scenes in Mexico were manufactured in the US.

Supreme Court Chief Justice John Roberts’ intervention came as the administration faced a midnight deadline (05:00 GMT on Thursday) to pay contractors.

Officials had argued that they could not process the payments within the timeframe set by a lower court judge.

Since coming to power in January, US President Donald Trump has taken quick action to end many aid programmes, largely run by the US Agency for International Development, USAID, and placed most of its staff on administrative leave or sacked them.

The Trump administration is seeking to shrink the federal workforce and cut costs in a drive led by Elon Musk.

The billionaire Trump adviser asked millions of bureaucrats over the weekend to list their accomplishments from the past week – sparking fury amongst the workforce and disagreement with officials leading the department.

US District Judge Amir Ali had ordered the US State Department and USAID to pay about $2bn-worth of bills (£1.6bn) to contractors by midnight on Wednesday.

It is one of many interventions by judges trying to stop or pause a wave of Trump administration orders.

As the deadline approached, the Trump administration went to the Supreme Court, arguing it was impossible to process claims in an orderly fashion in such a short period of time.

The US federal government freeze comes as the administration carries out a review of foreign aid funding.

Acting Solicitor General Sarah Harris said Judge Ali’s order “has thrown what should be an orderly review by the government into chaos”.

The cutbacks to USAID have already upended the global aid system.

Hundreds of programmes have been frozen in countries around the world since the president announced his intentions in January.

The US is by far the biggest single provider of humanitarian aid around the world.

It has bases in more than 60 countries and works in dozens of others, with much of its work carried out by its contractors.

According to the Associated Press news agency, the Trump administration wants to eliminate more than 90% of the USAID’s foreign aid contracts – and $60bn of US overseas aid.

Since taking office in January, he has ordered the suspension of all new asylum claims, cancelled refugee resettlement, frozen government hiring and spending, gutted agencies established by Congress, banned gender transition care for teenagers and offered a buyout deal for hundreds of thousands of federal workers.

The whirlwind of unilateral action on his campaign promises has pushed the limits of presidential power – and prompted legal challenges from Democrats, unions and legal groups. So far the federal courts have been the only substantive roadblocks to Trump’s agenda, as judges have temporarily suspended some of the most contentious proposals, including an end to automatic citizenship for anyone born on US soil.

But Trump is pressing on – and seems headed for a showdown with the judiciary that could eventually end in the highest court in the land. This week, a Rhode Island judge said the Trump administration was clearly and openly defying his court order to unfreeze billions in federal funds. The White House responded by saying that “every action” the president took was “completely lawful”.

If Trump’s orders do reach the US Supreme Court, six of the nine justices there – including three appointed by Trump in his first term – are conservative. Just last term, the court issued a decision holding Trump, and all future presidents, largely immune from prosecution for official actions while in office.

At the time, it was a landmark expansion of presidential authority. But some observers have suggested that Trump’s latest moves could be part of a strategy to expand his powers even further. If the high courts agree to uphold some of his executive orders, it could strengthen his ability to enact policy changes without the help of Congress.

And even if the courts rule against the president, says Ilya Shapiro, a constitutional expert at the Manhattan Institute, those legal defeats might be politically advantageous.

“There could be political benefits to being challenged in court and then even losing in court because then you can run against judges and make political hay of it.”

There is another scenario, however. Trump could simply refuse to comply with any court that tries to stop his exercise of unfettered presidential power.

In Oval Office comments on Tuesday, the president hinted that this might be an option, in his typically oblique way.

“We want to weed out the corruption,” Trump said. “And it seems hard to believe that a judge could say we don’t want you to do that.”

“Maybe we have to look at the judges,” he continued. “I think it’s a very serious violation.”

On Sunday, Trump’s vice-president, JD Vance, was even more blunt.

“Judges aren’t allowed to control the executive’s legitimate power,” he posted on the social media site X. That view was similar to one Vance expressed in a 2021 podcast, when he said that if Trump returned to power he should refuse to comply with any court order that prevented him from firing federal workers.

Directly defying a court ruling, however, would cut against centuries of US history and amount to the opening skirmishes in a constitutional crisis that pits the president against the branch of government designed to establish and interpret the law of the land.

“My read is that President Trump is testing the outer boundaries of what he might be able to get away with, doing a lot of things that are blatantly against the law and maybe some things that are closer to the line,” said Fred Smith, a professor at the Emory School of Law.

“They are breaking a lot of norms,” Smith added of the nascent Trump administration. “Why he is doing that, only he knows fully. But he is doing it.”

So far, Trump and his allies have made aggressive comments about unfavourable court decisions in the public and in legal filings, but have yet to be sanctioned for disobeying a court. When Trump was the target of multiple prosecutions over the past four years, he frequently questioned the legitimacy of the presiding judges, but his courtroom lawyers adhered to the law and legal procedures.

The federal judge in Rhode Island, who had placed a temporary hold on another Trump order to freeze some federal spending, did warn in court filings Monday that the administration was violating his temporary restraining order but stopped short of finding them in contempt.

Conservative legal scholar Ed Whelan wrote on X that it would be “extremely grave” for the Trump administration to defy a federal court order.

“I’m open to the argument that truly extraordinary circumstances (the makings of a wild hypothetical) might justify defiance,” Mr Whelan wrote. “But in our constitutional system there should be an overwhelming presumption in favour of executive-branch compliance with federal court orders.

Should Trump disobey, and therefore delegitimise, the courts, the decision could come back to bite him when the time comes for the president to see his own lawful agenda enforced, some legal experts say. Democratic states like California, for instance, might be inclined to ignore White House directives and federal laws they don’t like – and Trump would be hard pressed to use the courts to bring them to heel.

“If the executive decides it will obey some court orders but not others, it will find it won’t get any court orders that it wishes to obey,” said Philip Bobbitt, a constitutional scholar at Columbia University Law School. “I just don’t think they thought that through.”

When Donald Trump redecorated the Oval Office to his liking in January, he reinstalled a portrait of President Andrew Jackson that had hung on the wall across from the Resolute Desk in his first term.

The seventh US president is remembered for a critical moment of defiance against the United States Supreme Court. When the justices decided a dispute between the state of Georgia and Cherokee Indian governments in 1832, Jackson did not seem interested in following its direction.

Jackson allegedly said of the Chief Justice’s ruling, “John Marshall has made his decision; now let him enforce it!”

Nearly 200 years later, Trump himself has found himself on his own collision course with America’s judiciary.

The high court heard arguments about the transgender law on Wednesday and its decision, expected next year, could impact similar laws in 25 other states.

Three Tennessee transgender teenagers, their parents and a doctor have argued that the 2023 ban violates a US constitutional guarantee of equal protection, saying it discriminates based on sex.

The hearing was the first time that the current court, which has a conservative majority, openly discussed a significant battle in the US “culture wars”.

The Biden administration and US medical groups argue that the law prohibits transgender individuals from accessing drugs and therapies that are available to other adolescents with medical need. They also say it hinders parents’ rights to seek needed care for their children.

During hours of oral arguments on Wednesday, five of the Supreme Court’s nine justices expressed doubts on the legal challenge to the ban and the arguments made by lawyers for the families and the administration.

Chief Justice John Roberts questioned whether judges should decide what he described as a medical issue – saying such questions are traditionally left up to state lawmakers.

“The constitution leaves that question to the people’s representatives, rather than to nine people, none of whom is a doctor,” he said.

The court’s three liberal justices appeared to be firmly on the side of the Tennessee families.

Justice Ketanji Brown Jackson, compared the law to legislation prohibiting interracial marriages that was struck down in the 1960s.

“The laws here operate in the same way,” she said. “The question of ‘can you marry this other person’ depended upon what your race was.”

“I take your law to be doing basically the same thing,” she added.

Tennessee’s solicitor general, J Matthew Rice, pushed back and repeatedly argued that the law does not discriminate based on gender.

Mr Rice argued that the law is designed “to protect minors from risky, unproven medical interventions”.

In 2020, the Supreme Court ruled that federal law prohibits discrimination against transgender employees.

Earlier this year, the court also upheld an Idaho ban against transgender medical treatments involving children, but it did not express an opinion on the constitutionality of the statute.