A dozen Senate Republicans ended up joining all the chamber’s Democrats in approving the resolution. With the House having passed it last week, it goes to the president’s desk. Trump reiterated his intention to veto the measure ― which would mark the first such action of his presidency.

“We have to recognize that we have a crisis at the border ― 76,000 people crossing illegally in February alone,” Tillis said in his speech. “We have narcotics flooding our country.”

In a floor speech, the freshman lawmaker explained his change of heart by stressing the “crisis” theme that Trump has touted. But others saw political expediency at work.

Enough Republicans stuck to their guns Thursday to pass the resolution that seeks to block Trump’s declaration. But Tillis, a North Carolinian who had loudly gone public with his opposition to the president’s move, was not among them. In a flip-flop that gained much attention, Tillis stayed in Trump’s camp and voted against the measure.

Late last month, Sen. Thom Tillis declared he would be part of a cadre of GOP senators willing to make a rare break with President Donald Trump to vote against the national emergency he declared to achieve his prized southern border wall.

ASSOCIATED PRESS Sen. Thom Tillis, who won his seat in a tight race in 2014, faces a potentially tough re-election battle in 2020.

In a statement after the vote, Tillis expressed confidence that steps would be taken to stop “a future left-wing president” from using the same emergency authority Trump is exercising on the border issue to address matters such as climate change or gun violence. He also cited what he called Trump’s “historic commitment” to amend the emergency declaration law to prevent future abuse of it as a reason he changed his mind.

“The concerns I’ve raised were never about what President Trump is trying to accomplish but rather with setting a precedent that a future Democratic president would exploit to bypass Congress to implement policies well outside the mainstream,” Tillis said in his statement.

He was singing a dramatically different tune just about two weeks ago, however, when he warned in a splashy Washington Post op-ed that it would be hypocritical of Republicans to back Trump’s national emergency declaration after vehemently and often criticizing President Barack Obama for bypassing Congress in implementing policies on immigration and other contentious issues.

“Conservatives rightfully cried foul” when Obama “used executive action to completely bypass Congress and unilaterally provide deferred action (on deportation) to undocumented adults who had knowingly violated the nation’s immigration laws,” Tillis wrote. “Some prominent Republicans went so far as to proclaim that Obama was acting more like an ‘emperor’ or ‘king’ than a president.”

He said: “There is no intellectual honesty in now turning around and arguing that there’s an imaginary asterisk attached to executive overreach — that it’s acceptable for my party but not thy party.”

Tillis faces a potentially tough re-election fight in 2020. Amid anger among conservative activists sparked by his op-ed, momentum was gathering for a primary challenge targeting Tillis, with some urging Rep. Mark Walker (R-N.C.) to take him on. Tillis’ about-face in Thursday’s vote could cool some of this discontent.

Democrats also see Tillis’ seat as offering them a prime pickup opportunity in a year when they are setting their sights on winning a Senate majority. Possible Democratic candidates include Anthony Foxx, a former mayor of Charlotte, North Carolina, who served as Transportation secretary under Obama.

Tillis “made a big show about how he’d stand up for North Carolina but caved under pressure,” North Carolina Democratic Party spokesman Robert Howard said in a statement after the vote on the emergency declaration. “Tillis again reminded the entire state who he is: a spineless politician who won’t keep his promises and looks out for himself instead of North Carolina.”

Several political commentators weighed in on Twitter on Tillis’ vote: