President Donald Trump has officially declared a national emergency in order to secure funding for his border wall. But he’s also ready to be challenged in court, as he said at the announcement Friday morning.

“We will have a national emergency, and we will then be sued,” Trump said on Friday, outlining the steps he expected the lawsuit to take all the way to the Supreme Court.

Trump is issuing the declaration under the National Emergencies Act of 1976, which lets presidents issue an emergency declaration but under certain constraints — namely, Trump can only use specific powers Congress has already codified by law, and he has to say which powers he’s using. The act doesn’t define what counts as an emergency.

As Vox’s Sean Illing, who spoke with 11 experts about the legality of Trump’s declaration, laid out, there’s enough ambiguity in the law to let Trump declare an emergency. But the maneuver may not stand up to legal scrutiny once challenged in court. He is effectively trying to circumvent Congress — which is supposed to have the “power of the purse” and has decided against funding his border wall — and it’s not clear whether Trump can actually use the armed forces for the project. And his claim that there’s an emergency at the border that necessitates a border wall is dubious.

House Speaker Nancy Pelosi and Senate Minority Leader Chuck Schumer announced Friday that they were prepared to take multiple routes to try to block Trump’s efforts. “The Congress will defend our constitutional authorities in the Congress, in the Courts, and in the public, using every remedy available,” they said in a statement.

There are several different paths to challenging the declaration. Here are some of the most likely.

1) A joint resolution of termination contesting the status of the emergency

Congressional Democrats have already said they plan to use any means they have to oppose Trump’s national emergency, including a legislative check — a resolution contesting the status of the national emergency — that’s part of the National Emergencies Act of 1976.

Both chambers of Congress would need to approve the resolution by a simple majority (that’s 51 votes in the Senate and 218 votes in the House).

Reps. Joaquin Castro (D-TX) and Alexandria Ocasio-Cortez (D-NY) announced Friday that they are ready to introduce a bill in the House that would block the emergency declaration. Castro has previously said he was prepared to introduce this resolution in the House, where Democrats have a comfortable majority. It remains to be seen whether the Senate has the numbers to approve it: The 47-member Democratic caucus would need four Republicans to join them.

.@JoaquinCastrotx and I aren’t going to let the President declare a fake national emergency without a fight. https://t.co/iPlcVVsm6U — Alexandria Ocasio-Cortez (@AOC) February 15, 2019

If they can get the votes, the resolution then heads to Trump’s desk — where he’s expected to veto it. (It’s worth noting that Trump has threatened to veto many, many bills, but has yet to actually do so during his presidency.)

Because of his expected veto, stopping the declaration this way would require a veto-proof majority, which consists of a two-thirds vote in both the House and the Senate.

To reach that threshold in both chambers, Democrats would need the support of a hefty number of Republicans so they can get 67 votes in the Senate and 290 votes in the House. It’s unlikely this many Republicans would directly go up against the president.

2) Congressional Democrats sue the White House

As Pelosi and Schumer both mentioned, taking this fight to the courts is another possible means of blocking the emergency declaration — and there’s a precedent, one set by House Republicans.

House Democrats could sue the White House on the grounds that it is effectively bypassing Congress’s constitutional power of the purse, the same logic Republicans used in a 2014 lawsuit against the Obama administration.

At the time, Republicans argued that officials attempted to use federal funds that had not been approved by Congress to pay insurers under the Affordable Care Act. In that case, a federal judge ruled that Republicans had the grounds to sue the White House because its efforts infringed on Congress’s authority over appropriations.

House Democrats could also contest the status of the national emergency by arguing that it’s not actually an emergency at all, though experts have said that the law has typically granted the president a wide berth to determine what an emergency is.

3) Landowners sue the White House

Long before Trump’s emergency declaration, one likely source of resistance has been clear: people who own land along the US-Mexico border where Trump wants the wall to be built.

As the New York Times pointed out in 2017, dozens of lawsuits involving landowners in Texas were filed after President George W. Bush in 2006 signed the Secure Fence Act mandating fencing and walls be built along parts of the border. And in the case of Trump’s wall, the scenario is likely to be similar.

The federal government can legally invoke “eminent domain,” a power to take private land or property and convert it into public use enshrined within the US Constitution, but if Trump tries to do so for the border well, he could very well face a fight. Landowners could sue, as they did after Bush’s order, to keep the government from taking their land. And those lawsuits could last for a long time: the Washington Post in January reported that 334 eminent domain lawsuits were filed in South Texas under the Bush administration, and 60 to 70 of them are still pending.

4) Liberal activist groups sue the White House

The ACLU, which has filed multiple lawsuits against the Trump administration, on Friday said it planned to sue the president over his “blatantly illegal declaration of a national emergency.” The group called Trump’s move an “unconstitutional power grab that hurts American communities.” In a statement, ACLU executive director Anthony Romero cited Trump’s Rose Garden remarks, when Trump said he doesn’t “need” to declare an emergency “but I’d rather do it much faster.”

“He just grew impatient and frustrated with Congress,” Romero said.

NEW: ACLU announces intention to file legal challenge against Pres. Trump's national emergency declaration.



“By the president’s very own admission in the Rose Garden, there is no national emergency." https://t.co/k2gSvnfMog pic.twitter.com/yegRNE5KSC — ABC News (@ABC) February 15, 2019

Ahead of the declaration, nonpartisan nonprofit Protect Democracy and think tank the Niskanen Center said they were prepared to file a lawsuit. They are representing El Paso County and the Border Network for Human Rights. Trump traveled to El Paso for his first 2019 campaign rally, in part to highlight his calls for a border wall, and during the State of the Union falsely claimed border fencing reduced crime there.

El Paso County Judge Ricardo Samaniego in a statement slammed Trump for his “many negative and false statements about our community in the attempt to justify his border wall.” He continued, “He has never reached out to the leadership of our community to determine if this is actually an emergency. This threatened emergency declaration will further damage El Paso County’s reputation and economy, and we are determined to stop this from happening.”

5) California and other states sue

Soon after Trump’s announcement on Friday, the state of California set in motion plans to file a lawsuit against his emergency declaration.

Democratic Gov. Gavin Newsom and California Attorney General Xavier Becerra said that Trump was “manufacturing a crisis and declaring a made-up ‘national emergency’ in order to seize power and subvert the constitution” in a joint statement on Friday. “Our message back to the White House is simple and clear: California will see you in court.”

Becerra had already telegraphed the move in his Spanish-language response to Trump’s State of the Union address.

California isn’t the only state poised to challenge Trump’s declaration. Nevada Attorney General Aaron Ford in a statement said the Trump administration “should be prepared for a legal challenge” should Nevada’s federal funds be affected. Other states could resist as well.

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