(CNN) A bipartisan group of more than 100 former members of the House of Representatives filed a court brief Tuesday in a case challenging the President's national emergency declaration.
The case, brought by the House of Representatives, seeks to block President Donald Trump from circumventing Congress to fund his signature border wall.
"Rarely in our Nation's history has the Executive Branch launched such an assault on Congress's exclusive legislative powers," the amicus brief says, citing the President's national emergency declaration that allowed him to circumvent Congress and obtain funds for his border wall.
"Without action by this Court to prevent the Administration's usurpation of congressional authority, the unchecked expansion of the Executive's power at the expense of the Legislative Branch will threaten our democracy," it continues.
Among the points laid out in the brief, the former lawmakers refute the idea that there's a national emergency at the southern border. "Emergencies are sudden and immediate, not longstanding and static," the brief says, noting that Trump had called for a wall dating back to the start of his campaign in 2015.
Among those who joined the briefing today are former House Majority Leader Dick Gephardt and two former House members and Secretaries of Defense Bill Cohen and Leon Panetta.
A day earlier, eight former House general counsels who served under both Republican and Democratic speakers over the past four decades filed an amicus brief in the case.
The lawsuit was filed in the US District Court for the District of Columbia. The Justice Department's response to the suit is due Wednesday.