Republican Sens. Lamar Alexander, of Tennessee, and Mitt Romney have endorsed a resolution passed by the Democratic-controlled House to block President Donald Trump from using emergency powers to fund his long-promised U.S.-Mexico border wall.
That brings to seven the number of Republicans who have announced they will cross Trump on a vote expected for Thursday afternoon, ensuring the measure will pass.
Romney was the GOP's 2012 presidential nominee and a sometimes critic of Trump; Alexander is among the senior guardians of the Senate as an institution. Lawmakers oppose Trump's action because they see the power of the purse as Congress' prerogative.
Romney said that "this is a vote for the Constitution and for the balance of powers that is at its core."
Trump has promised to veto the measure and is sure to be sustained by his House GOP allies.
Sen. Marsha Blackburn, R-Tenn., said Thursday she supports Trump's measure.
"Since Congress gave emergency powers to the executive branch in 1976 under the National Emergencies Act, presidents from both political parties have declared national emergencies in the United States over situations far less dire than the security and humanitarian crisis that is currently plaguing the southern border," she said in a statement. "The President and Congress must take swift action to secure our border, protect our citizens, and defend our sovereignty. I support President Trump's declaration of a national emergency and I reject the resolution of disapproval."
The full statement from Alexander:
"I support the president on border security. I have urged him to build the 234 miles of border wall he has asked for in the fastest possible way by using $5.7 billion already approved by Congress. But his declaration to take an additional $3.6 billion that Congress has appropriated for military hospitals, barracks and schools is inconsistent with the U.S. Constitution that I swore an oath to support and defend.
"Never before has a president asked for funding, Congress has not provided it, and the president then has used the National Emergencies Act of 1976 to spend the money anyway. The problem with this is that after a Revolutionary War against a king, our nation's founders gave to Congress the power to approve all spending so that the president would not have too much power. This check on the executive is a crucial source of our freedom.
"This declaration is a dangerous precedent. Already, Democrat presidential candidates are saying they would declare emergencies to tear down the existing border wall, take away guns, stop oil exports, shut down offshore drilling and other leftwing enterprises - all without the approval of Congress."