Utah Sens. Mike Lee and Mitt Romney both voted in favor of a resolution to stop President Donald Trump's national emergency declaration.
The resolution from House Democrats blocks Trump from funding his proposed border wall without congressional approval. The measure passed the Senate 59-41 on Thursday.
Romney said his vote was not about border security, but about proper process.
"I'm sure he would rather have me vote in a different direction," said Romney. "But this, for me, is a matter of defending the Constitution."
Sen. Lee attempted to strike a deal with the White House earlier this week with legislation designed to limit the ability of presidents to use emergency powers in the future, but those talks broke down.
President Trump has threatened to veto the resolution.
Watch the clip below via CNN: