Washington (CNN)Senate Republicans are unmoved by the stunning allegations in former national security adviser John Bolton's forthcoming book, saying Bolton's accusation that President Donald Trump sought reelection help from Chinese President Xi Jinping did not change their minds against calling him as a witness in the impeachment trial.

       The reaction amounted to the latest example of most Republicans shrugging their shoulders at the steady stream of controversies surrounding the President -- whether it was the clearing out of peaceful protesters near the White House, him floating a baseless conspiracy theory about an injured Buffalo demonstrator or seeing his former Secretary of Defense, James Mattis, call Trump a threat to the Constitution.

       Republicans on Capitol Hill are growing used to ignoring the controversies -- even from something as serious of allegedly inviting a foreign power to help him win his reelection --- as they battle to keep control of the Senate with the help of the President.

       Asked about Bolton's allegation Trump explicitly tied an ask for China to boost purchase of agriculture products to help his reelection, GOP Sen. John Barrasso said: "Every President has, one way or another, thought they ought to be reelected. I think President Trump should be reelected. I support his reelection, I'm for it."

       Bolton accused House Democrats of committing " impeachment malpractice" by not broadening out their impeachment investigation beyond Ukraine, and he wrote that Trump told him US aid to Ukraine should not be released until an investigation was conducted into his 2020 rival, former Vice President Joe Biden.

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       All but two Senate Republicans voted against hearing from Bolton or any other witnesses in the Senate's impeachment trial earlier this year after the House's impeachment. They said Thursday that Bolton's new book hasn't changed their minds, while many declined to weigh in on the allegations themselves.

       "No. We never should have had an impeachment trial," said Sen. Ron Johnson, a Wisconsin Republican, when asked if the Senate should have called Bolton as a witness.

       "The House didn't think it was important," said Sen. Cory Gardner, a Colorado Republican up for reelection in 2020, repeating a criticism Senate Republicans leveled frequently during the Senate trial.

       Asked about his reaction to Bolton's allegations that Trump told Xi it was the right call to build concentration camps for Uyghur Muslims, Gardner interrupted the question to say, "I haven't read the book."

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       Sen. Marco Rubio, a Florida Republican who introduced the Uyghur Human Rights Policy Act that Trump signed Wednesday, said he had no reason to believe Bolton was lying about Trump's comments, but he didn't have proof it was true either.

       "I don't know if that happened, because I'm not in the meeting," he said on Thursday. "I can't opine on a meeting I wasn't in."

       In the book, Bolton writes about multiple episodes where Trump sought to help foreign leaders. He charges that Trump told Turkish President Recep Tayyip Erdogan he would "take care of things" after Erdogan raised a federal investigation into a Turkish bank violating Iranian sanctions. Bolton also writes that Trump urged Xi to buy US agriculture products to help his reelection prospects.

       "He stressed the importance of farmers, and increased Chinese purchases of soybeans and wheat in the electoral outcome," Bolton writes.

       Barrasso, a Wyoming Republican and a member of the Senate GOP leadership, dismissed the allegations that Trump was seeking reelection help from Xi. "Different people use different sales techniques. I'm for selling agriculture. I'm from Wyoming. We want agriculture products sold to China," Barrasso said.

       Asked about Bolton's allegation Trump explicitly tied it to his reelection, Barrasso said: "Every president has, one way or another, thought they ought to be reelected. I think President Trump should be reelected. I support his reelection, I'm for it."

       During the impeachment trial, Democrats had hoped to sway moderate Republican senators, Lisa Murkowski of Alaska and Lamar Alexander of Tennessee, to vote to subpoena Bolton and other witnesses. Both ultimately voted against hearing from witnesses.

       Murkowski said Thursday she did not regret that decision in light of the new allegations from Bolton.

       "I made the decision that I made at the time that I made it and there's no going back," Murkowski said. "I don't regret that decision. Like I said, there's no going back."

       Alexander argued Thursday that he didn't "need any more witnesses to prove to me that the President did what he was accused of doing."

       "What I said was that was inappropriate, but it was not something for which the President of the United States should be removed from office for," Alexander said.

       Several Republicans declined to comment on Bolton's allegations Thursday. Senate Majority Leader Mitch McConnell was silent when asked by a reporter for his reaction to Bolton telling ABC News in an interview that Trump was "unfit for office."

       Bolton's potential testimony swirled over both the House's impeachment inquiry and the Senate's impeachment trial, as Trump's national security adviser was involved in key episodes of the House's allegations that Trump pressured Ukraine to investigate Biden while withholding a White House meeting and $250 million in security aid.

       The House sought Bolton's testimony, but he threatened to file a lawsuit if he was subpoenaed, and House Democrats opted not to take the matter to court. Then Bolton said he was willing to testify in the Senate trial, but the Senate voted 51-49 to dismiss a motion to subpoena him. Republican Sens. Susan Collins of Maine and Mitt Romney of Utah voted in favor of the subpoena.

       "I think it's the House's job to impeach. I think it's the Senate's job to try," said Sen. Todd Young, an Indiana Republican. "So, there was a full record admitted in. We don't need to relitigate that."

       House Intelligence Chairman Adam Schiff, a California Democrat who led the House's impeachment investigation, told CNN's Erin Burnett on "OutFront" Thursday that "we have just begun discussions with leadership about what next steps are appropriate to find out more about what John Bolton experienced, saw, witnessed in terms of the President's wrongdoing."

       "I think it's worth making sure we understand just how (Trump) has exposed and undermined the country, but how we do that, we're still in the process of discussing," Schiff added.

       House Speaker Nancy Pelosi criticized Bolton at a news conference Thursday, saying he was "so arrogant" in refusing to testify and then criticizing Democrats for not spending more time on the matter.

       "We'll make a judgment," she said if the House would respond to Bolton. "We'll be discussing how the American people are best served by oversight. The public has a right to know."

       This story has been updated with additional developments Thursday.

       CNN's Lauren Fox, Ali Zaslav and Caroline Kelly contributed to this report.

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