(CNN) Sen. Bob Corker is facing the ire of the White House after forging ahead with his plan to curtail the President's power on trade.
President Donald Trump told the Tennessee Republican in a "lengthy" call Wednesday to back off legislation to rein in his power to levy huge tariffs on US allies, seeking to head off a confrontation with Republicans in Congress.
But the Tennessee Republican told Trump that he planned to press ahead, even as the Senate Foreign Relations chairman acknowledged that some of his colleagues were "fearful" of crossing the President despite their objections to his tariff policy.
"He's not pleased with the effort," Corker, who is retiring at the end of his term, told CNN, referring to Trump.
Corker described the call as "lengthy" and asked if it became tense, Corker said "we had a heartfelt conversation."
Corker unveiled legislation Wednesday afternoon that would require lawmakers to approve of trade actions by the President that are done on the grounds of national security. But, Corker's push could face an even tougher climb in the Senate now that the White House has weighed in.
"I am a United States senator, and I have responsibilities and I'm going to continue to carry them out," Corker said, pushing back on Trump.
While many Republicans -- including GOP leaders -- have released blistering statements and worked behind the scenes to encourage Trump to change his mind on enacting steel and aluminum tariffs on US allies in the European Union, Canada and Mexico, Republicans leaders have shown very little appetite to actually defy Trump legislatively in recent days.
"I understand there's a fear-- fearful of the president, let's be honest," Corker said of his Senate GOP colleagues. "On policy grounds, they strongly support this. But there are concerns about countering the president by some. ... But there's no doubt fear out there."
Republican leaders have balked at the idea of using legislation to stop Trump with House Speaker Paul Ryan -- who opposed aluminum and steel tariffs last week -- telling reporters Wednesday morning that there was little appetite to pass legislation in the House similar to Corker's.
"You would have to pass a law that he would want to sign into law and that, that would be what it would take," Ryan said. "You can do the math on that."
Republicans say they are fearful of going head to head with Trump on trade especially in a midterm election year. After all, trade was one of the top campaign issues for the President even as he challenged traditional GOP orthodoxy on his way to win victories in Rust Belt states like Ohio, Michigan and Wisconsin.
"None of us want to go up (against Trump). We want to see the President succeed," said Sen. Mike Rounds, a Republican from South Dakota. "We want to be part of a winning team when it comes to getting his policies in place. They're working, but at the same time, we have an obligation to take a hard look at the delegation of authority we have provided to him and whether or not that has been properly used."
Corker told reporters Wednesday that some Republicans are "fearful" of crossing Trump by signing onto the bill, making it more and more unlikely that the legislation gets through the Senate at all.
This story has been updated.