House Democrats mulling a legal challenge to President Donald Trump's plans to secure funding for a border wall may have a blueprint in a legal attack Republicans mounted against the Obama administration nearly five years ago over payments related to the Affordable Care Act.

The House of Representatives, under a Republican majority led by then-Speaker John Boehner, sued the Obama administration and the Health and Human Secretary Sylvia Burwell in 2014 to challenge the administration's use of federal dollars to fund cost-sharing reduction payments to health insurers. Those payments were made even though Congress had not authorized them.

While that case ultimately settled, a federal judge found the House had standing to sue the administration. And while the opinion is not considered precedential, lawyers see clear parallels between it and a potential legal challenge that House Democrats could launch to thwart Trump's border wall.

After failing to secure funding for border wall construction, the president invoked his emergency powers last week to redirect money that Congress appropriated for other purposes, including military construction funds.

Kerry Kircher, the House general counsel when the Republican majority sued the Obama administration, said he could see the 2014 lawsuit serving as a potential “template” for House Democrats, who've decried Trump's move as an end run around the Constitution.

“At bottom, you are talking about the same basic constitutional responsibility that the House will claim is being usurped: the appropriations authority,” Kircher said.

If the House sues the administration, the Justice Department will likely defend the president by challenging the lawmakers' standing, Kircher said. In that instance, they'd be wise to pay close attention to a 2015 opinion from U.S. District Judge Rosemary Collyer in D.C., who held the House had standing to sue the executive branch over the cost-sharing reduction payments.

“Neither the President nor his officers can authorize appropriations; the assent of the House of Representatives is required before any public monies are spent,” Collyer, a George W. Bush appointee, wrote in her decision. “Congress's power of the purse is the ultimate check on the otherwise unbounded power of the Executive.”

On the merits, the two cases would be different, said David Rivkin, a Baker & Hostetler partner who, along with Florida International University law professor Elizabeth Price Foley, worked with the House in the early stages of its lawsuit.

“From the perspective of standing, the situations are very, very similar and almost identical,” Rivkin said. Rivkin added he could see the House arguing that Trump's move “vitiates their core constitutional power, the power of the purse, and it's an institutional injury.”

In general, the courts have been reluctant to second-guess a president's national security and emergency determinations. But Bill Pittard, who served as the House's deputy general counsel during the Obamacare payments legal fight, believes this case could prove to be the exception.

Courts could be reluctant to define or restrict the use of a national emergency, Pittard said, but they may also be wary of giving too much power to the executive at the expense of the legislative branch.

Democratic lawmakers, for their part, have said they will explore all options. House Speaker Nancy Pelosi, and Senate Minority Leader Chuck Schumer, have vowed to “defend our constitutional authorities in the Congress, in the Courts, and in the public, using every remedy available.”

That might not necessarily mean a lawsuit. House Democrats could instead opt to back other plaintiffs suing the Trump administration by filing amicus curiae briefs.

Either way, House Democrats will likely try to pass a joint resolution first in order to terminate Trump's emergency declaration. Under the National Emergency Act of 1976, the House or Senate could pass a resolution to revoke a president's emergency declaration, which would then have to pass the other chamber. Even then, it's unlikely Congress would be able to override a Trump veto.

Other parties have also promised to be a check on Trump's power. A group of 16 state attorneys general, led by California Attorney General Xavier Becerra, sued the Trump administration Monday, claiming the states would be harmed by the diversion of funds.

A trio of South Texas landowners and an environmental group, represented by the nonprofit group Public Citizen, also sued Trump in Washington, D.C., last week, and three wildlife conservation groups followed with another lawsuit shortly afterward.

More groups have vowed to join the legal fray, including nonprofit Protect Democracy and the Niskanen Center. The American Civil Liberties Union, too, has promised to sue the administration.

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