Senator Marco Rubio, Republican of Florida, on Sunday brushed aside former President Donald J. Trump’s comments suggesting that he might not defend NATO allies and that he would encourage Russia to “do whatever the hell they want.”

Mr. Trump made the comments at a rally on Saturday in South Carolina but did not make clear that, though there was a dispute over some European countries meeting their spending commitments to their own militaries, there was no debt owed to the alliance.

Mr. Rubio, the vice chairman of the Senate Intelligence Committee, suggested in an interview on CNN’s “State of the Union” that Mr. Trump was simply describing how he had “used leverage to get people to step up to the plate,” and echoed a line that Republicans have used for years to dismiss Mr. Trump’s statements of his intentions: “He doesn’t talk like a traditional politician.”

Mr. Rubio also shrugged off Mr. Trump’s mocking comments about Nikki Haley’s husband, who is deployed in Djibouti, and suggested that nothing Mr. Trump said could shake his support for the former president.

“One of the things I’m not going to do any longer is respond to every comment Donald Trump makes and say, ‘Do you still support him?’” he said. “I do. And I support him because Joe Biden’s a disaster.”

In the interview, Mr. Rubio also denounced bipartisan border-security legislation that contains provisions that Republicans have long pushed for but that Mr. Trump has come out against, saying not only that it didn’t go far enough but that it didn’t even improve on the status quo. “It’s not better than nothing,” Mr. Rubio said after the host, Jake Tapper, played a clip of the president of the border agents’ union — which has supported Mr. Trump and pilloried President Biden’s border policies — saying the bill was “a step in the right direction.”

Mr. Rubio zeroed in on a provision that would enable asylum officers to grant immediate asylum to people who showed a dire need, though the bill would raise the bar for asylum claims overall and close the border if the number of migrants whom border officials encountered averaged more than 5,000 a week.

“They want to turn a bunch of illegal immigrants into citizens, into voters, in the hopes that those people will then turn around and vote for them in future elections, grateful because they’ll know who let them in,” he said.