Sen. Rand Paul said Wednesday that he would do whatever necessary — including joining a filibuster by Senate Democrats — to block confirmation of Donald Trump’s Cabinet nominees if he taps someone like John R. Bolton or Rudolph W. Giuliani for secretary of state.

Mr. Paul’s unequivocal opposition to some of the names floated for key posts in the next presidential administration was the first sign that Mr. Trump can’t count on the Republican majority in Congress to toe the line for him.

Several Senate Republicans refused to make early commitments to supporting any of the possible picks to Cabinet posts.

“I’ll do whatever I can to stop either Giuliani or Bolton because I don’t think that they support the president-elect’s foreign policy views,” said Mr. Paul. “I’m not doing this to oppose President-elect Trump. I’m doing this to help him. I endorsed him.”

Mr. Paul and some of his Republican colleagues warmly received other possible nominations, such as Sen. Ted Cruz for U.S. attorney general.

Mr. Cruz, an accomplished lawyer and staunch conservative from Texas, also was mentioned for the Supreme Court, but the Trump transition team signaled that the senator was not in the running for the high court.

Still, Mr. Bolton, Mr. Giuliani, Mr. Cruz or almost anyone else nominated by Mr. Trump can expect a confirmation fight from Democrats in the narrowly divided Senate.

“They are not going to be pleased with whoever is put up,” said Sen. Orrin G. Hatch, a Utah Republican who vowed to let Mr. Trump pick his own team.

Mr. Paul, a libertarian-leaning Kentucky Republican, said he backed Mr. Trump because of their shared opposition to the Iraq War and policies for regime change. But he said Mr. Giuliani, a former New York mayor, and Mr. Bolton, a former U.S. ambassador to the United Nations, did not hold those views.

Mr. Bolton has a reputation as a hawk, and Mr. Giuliani has made statements supporting interventionist foreign policy such as military action against Iran.

“I think there are several members of the caucus who are uncomfortable with both Bolton or Giuliani,” Mr. Paul said.

He did note a “groundswell of support” for Sen. Bob Corker of Tennessee, the Senate Foreign Relations Committee chairman who said he is under consideration to lead the State Department.

Speculation about Cabinet picks ran amok as the Trump transition team plodded through the selection process.

Rep. Lou Barletta, a Pennsylvania Republican and member of the Trump transition team, said the billionaire businessman deserved wide berth in assembling his administration.

“There is nobody more qualified to hire key people than an executive like Donald Trump, much more so than any politician who has never hired anyone more than their staff,” Mr. Barletta said.

Rejecting criticism about the pace of progress, transition team spokesman Jason Miller said Mr. Trump and Vice President-elect Mike Pence, who is leading the team, were working methodically to make the best choices.

“We’re not going to rush,” he told reporters at Trump Tower in New York, where Mr. Trump lives and the transition team has offices. “We’re going to make sure that they are people that we are confident will pass confirmation, and they are going to be people that we think can implement the president-elect’s vision.”

For the Supreme Court, Mr. Trump is sticking to the list of 21 candidates he identified during his campaign, apparently eliminating Mr. Cruz from contention.

Leonard Leo, executive vice president of the conservative Federalist Society, told reporters after meeting with Mr. Trump, “My understanding from our discussion today is that is still the list and that he is committed to evaluating those people very carefully, honing that list and then ultimately making a nomination upon his assumption of the office.”

The revelation was a blow to conservatives eager to see Mr. Cruz on the high court. But Mr. Cruz, who met Tuesday with Mr. Trump, could get the top Justice Department job.

Another conservative favorite in the Senate, Mike Lee of Utah, was on the list of 21 potential Supreme Court nominees that the Trump campaign released in September.

Mr. Leo said Mr. Trump summoned him to Trump Tower to talk about the importance he placed on replacing the late Justice Antonin Scalia.

The Federalist Society and the conservative Heritage Foundation helped Mr. Trump select the jurists on the list.

Former Trump campaign manager Kellyanne Conway also stressed that Mr. Trump was working from the original list.

“The list has not changed,” she told reporters. “President-elect Trump has committed to choosing his Supreme Court justices, particularly the vacancy created by the untimely death of Justice Scalia, [and] he’s committed to choosing from that list of 21.”

The jurists on the list are all conservatives who are committed to a literal interpretation of the U.S. Constitution.

Sign up for Daily Newsletters Manage Newsletters

Copyright © 2020 The Washington Times, LLC. Click here for reprint permission.