Liberal advocacy group Public Citizen on Friday filed the first lawsuit seeking to block President Trump Donald John TrumpOmar fires back at Trump over rally remarks: 'This is my country' Pelosi: Trump hurrying to fill SCOTUS seat so he can repeal ObamaCare Trump mocks Biden appearance, mask use ahead of first debate MORE’s national emergency declaration to allocate government funds for his proposed border wall.

The consumer rights think tank is suing on behalf of the Frontera Audubon Society and three landowners in South Texas who were told their land would be used to construct the barrier.

The lawsuit is expected to be the first of many challenging the declaration, which appropriated $8.1 billion for the wall.

ADVERTISEMENT

“The complaint urges the court to find that Trump exceeded his constitutional authority and authority under the National Emergencies Act, and to hold that the declaration violates the doctrine of separation of powers that is so central to our Constitution," Public Citizen said in a press release.

"The court should bar Trump and the U.S. Department of Defense from using the declaration and funds appropriated for other purposes to build a border wall, the complaint requests,” it added.

Trump predicted when announcing the emergency declaration at the White House earlier Friday that it would likely face legal challenges.

“We will possibly get a bad ruling, and then we'll get another bad ruling and then we'll end up in the Supreme Court,” Trump said, adding he believes his administration would prevail at the high court.

“I didn't need to do this, but I'd rather do it much faster,” he added, referring to constructing barriers on the border.

California Gov. Gavin Newsom (D) also said Friday he intends to sue the White House over the declaration.

“President Trump is manufacturing a crisis and declaring a made-up ‘national emergency’ in order to seize power and subvert the constitution,” Newsom said in a statement. “Our message back to the White House is simple and clear: California will see you in court.”

Democrats on the House Judiciary Committee announced they will investigate the declaration and have demanded testimony from the White House counsel and Justice Department officials, saying the national emergency shows “disregard” for the separation of powers and Congress’ purview over the federal budget.