Considering that 70% of Republicans support the border wall (albeit not necessarily via declaration of a national emergency), Republican congressmen would be in a tough situation, and it is seemingly unlikely that the majority of Republican senators would vote to override the President's veto.
California Attorney General Xavier Becerra, a Democrat, said he planned to work with other states to take legal action against the White House. "Because the emergency declaration is unlawful, the President lacks statutory authority to direct the spending of funds for that goal; the expenditure of monies from the United States Treasury for a border wall for which Congress has refused to appropriate funds violates Article I of the Constitution".
"All together in terms of what we already have underway, what's underway right now, and then what we're going to complete", he said.A senior administration official said that the White House is mulling to move Dollars 8 billion in currently appropriated or available funds towards the construction of the wall.
"If we give away, surrender the power of the purse, our most important power, there will be little check and no balance left", says Rep. Adam Schiff, (D) California.
"It is illegal for the commander in chief to use military resources for domestic law enforcement, except where explicitly authorized", he said, adding that no explicit authorization exists.
"Whatever your politics, every American should worry about President Trump's attempt to bypass the U.S. Congress by inventing a national emergency".
In an appearance on "PBS News Hour", Leon Panetta, a former Defense Secretary and director of the Office of Management and Budget, raised questions as to whether Trump can declare a national emergency for a campaign promise. "Based on that, we can do an assessment of what would be appropriate", he said.
Wallace noted that of the 59 times the 1976 National Emergencies Act was invoked by a president, only two were for military construction funds, which Trump plans to use: during the Gulf War and after 9/11.
After the president made the declaration on Friday, Sen. Democrats are preparing a joint resolution to repeal the national emergency in coming weeks, and they expect that some Republicans will cross the aisle to pass it.
'I look forward to our congressional delegation and Alaskans joining me in support of the president's mission to secure our borders.
Trump is weaponizing a serious national security statute as a vehicle for political expediency that sets a unsafe precedent for future Presidents and their use of power. If they do, the Republican controlled Senate would be forced to vote on it. El Paso County, Texas and three nonprofit organizations argued that the declaration violates the separation of powers and will cause economic dislocation and other damage in the border area.
"Frankly, I think there's enough people in the Senate who are concerned that what he's doing is robbing from the military and the [Department of Defense] to go and build this wall", Duckworth said.
"If Trump succeeds in using emergency powers to build the wall and seize property through eminent domain, future presidents could exploit this unsafe precedent".
Anyone directly affected by the order can challenge it in court, which Ms Elizabeth Goitein - co-director of the Brennan Centre for Justice's Liberty and National Security Programme - said will nearly certainly happen in this case. He should have sensed their entrenchment before the shutdown, and rather than threaten a National Emergency afterward, he should have early on signed another "disgusting" Continuing Resolution that didn't contain immigration legislation, and quickly moved to a Declaration; but, he didn't.