Trump has vowed to veto the resolution, ensuring he gets the funds he needs to fulfill a long-held campaign promise. Still, the vote shows Congress standing against the president’s decision to override the body’s constitutional power of the purse.

The Republicans that sided with Democrats include Sens. Susan Collins of Maine, Mitt Romney of Utah, Rand Paul of Kentucky, Marco Rubio of Florida, Lamar Alexander of Tennessee, Roy Blunt of Missouri, Mike Lee of Utah, Jerry Moran of Kansas, Lisa Murkowski of Alaska, Rob Portman of Ohio, Pat Toomey of Pennsylvania, and Roger Wicker of Mississippi, NBC News reports.

While not all oppose Trump’s border wall, many Republicans were wary of the precedent Trump’s national emergency would set. Trump declared the emergency in February after failing to receive the full $5.7 billion he desired for border wall funding—even after a 35-day government shutdown—allowing him to circumvent Congress to reallocate funds.

Thursday’s decision “is a vote for the constitution and for the balance of powers that is at its core,” said Romney, according to NBC. “For the executive branch to override a law passed by Congress would make it the ultimate power rather than a balancing power.”

Prior to the vote, Trump tweeted in the early hours of Thursday that he is “prepared to veto, if necessary,” adding that “the Southern Border is a National Security and Humanitarian Nightmare, but it can be easily fixed!”

After the Senate’s decision was announced, Trump restated his position, tweeting “VETO!” The veto would be the president’s first since taking office in 2017. It’s unlikely the Senate would have the two-thirds majority needed to override the veto.