WASHINGTON (Reuters) - President Barack Obama’s legal defense of some key initiatives including his signature healthcare law is collapsing as courts put cases on hold until after President-elect Donald Trump, hostile to the policies, assumes office on Jan. 20.

U.S. President-elect Donald Trump and Softbank CEO Masayoshi Son exit together after meeting at Trump Tower in Manhattan, New York City, U.S., December 6, 2016. REUTERS/Brendan McDermid

The pending conservative legal challenges could undo important elements of Obama’s presidential legacy if Trump, as expected, opts not to defend the Obama policies in court or simply ditches the initiatives that are under attack.

Since Trump’s election on Nov. 8, various courts have delayed action in three groups of cases that will not be resolved before Obama leaves office and blocked an administration regulation from going into effect in another.

They include a challenge by House of Representatives Republicans to an important provision in the Obamacare law, and cases concerning religious objections to that law’s mandate that employers provide health insurance coverage for birth control.

They also include Obama’s executive action, put on hold by the Supreme Court in June, to spare from deportation millions of immigrants in the country illegally, and his administration’s bid to extend overtime protections for workers.

Republican-governed states like Texas were behind some of the biggest challenges to Obama policies.

“We have a host of cases pending against the federal government due to the Obama administration’s overreach,” said Marc Rylander, a spokesman for Texas Attorney General Ken Paxton, a Republican who has sued the administration on various issues including immigration. Rylander said Texas officials “will continue to pursue all of these cases and look forward to working with a new administration.”

The U.S. Court of Appeals for the District of Columbia Circuit on Monday put on hold the House Republican Obamacare challenge until at least Feb. 21.

Trump and Republican congressional allies have said they plan to repeal and replace the law, meaning the case could become moot.

The Obama administration opposed the delay in that case, but agreed to put on hold its effort to revive Obama’s 2014 immigration plan.

The administration and the states that challenged the plan filed a joint motion on Nov. 18 saying the case should be put on hold “given the change in administration.” Trump has vowed to crack down on immigrants in the country illegally and is expected to abandon Obama’s blocked policy.

BIRTH CONTROL COVERAGE

The series of cases pending in lower courts concerning efforts by Christian groups to obtain an exemption to a provision of the Obamacare law requiring employers to provide health insurance coverage for contraceptives are also in a holding pattern. The Supreme Court sent the cases back to lower courts in May, throwing out several rulings in favor of the administration.

The lower courts are now awaiting the change in administrations.

In one of the cases, before the New Orleans-based 5th U.S. Circuit Court of Appeals, lawyers for some of the religious groups said in court papers that a delay “will afford the newly-inaugurated president and new administration an opportunity to take a fresh look at this litigation and consider potential resolutions acceptable to all sides.”

In the labor case, a federal judge on Nov. 22 prevented Obama’s regulation to extend mandatory overtime pay to more than 4 million salaried workers from going into effect on Dec. 1 as scheduled. That will give Trump leeway to change course when he takes office.

So far, courts have not delayed action on several other cases involving key Obama policies, including a state and industry challenge to rules to curb greenhouse gas emissions mainly from coal-fired power plants. An appeals court in Washington heard oral arguments in September but has not yet issued a ruling.

Trump has said he plans to rescind the regulation.

Meanwhile, the Supreme Court has agreed to decide a major transgender rights case that hinges in part on the Obama administration’s policy position in support of a female-born transgender high school student named Gavin Grimm, who identifies as male and sued in 2015 to win the right to use the school’s boys’ bathroom.

The court has not yet scheduled oral arguments in the case. It is due to rule by the end of June.