A political battle is underway over President Trump’s nominee for the key post of undersecretary of defense for policy, with both the vice president and defense secretary voicing support for the key Pentagon pick.

Several Republican senators, including Senate Intelligence Committee Chairman Tom Cotton of Arkansas, are reportedly questioning the choice of Elbridge Colby, citing the nominee’s views on China and other national security issues. The position requires Senate confirmation and several Republicans in the upper chamber are reportedly questioning Mr. Colby’s past policy positions.

Vice President J.D. Vance joined the fight Sunday on X, taking issue with those who say Mr. Colby has roots in the Obama wing of the Democratic Party and worked for a Democratic think tank, the Center for New American Security. After he left the Pentagon in 2018, Mr. Colby also worked for WestExec Advisers, a consulting firm founded by Biden administration Secretary of State Antony Blinken.

“Bridge has consistently been correct about the big foreign policy debates of the last 20 years,” Mr. Vance said. “He was critical of the Iraq War, which made him unemployable in the 2000s-era conservative movement.”

Defense Secretary Pete Hegseth is also backing the nominee, saying on X that Mr. Colby “was nominated because he will faithfully implement the President’s policy agenda — unlike many national security appointees in the first term who sought to undermine President Trump.”

Presidential adviser Elon Musk also asked what the concerns are regarding Mr. Colby. “Why the opposition to Bridge? What does [Mr. Cotton] think Bridge will do?” Mr. Musk stated on X.

Mr. Colby held the relatively minor position of deputy assistant defense secretary for strategy during the first Trump administration. It is unusual for someone who held that level position to be picked for the plum job of policy undersecretary, considered the No. 3 job in the Defense Department with a critical voice on policy.

Mr. Colby, an outspoken presence on social media commenting on national security issues,  received a boost from Tucker Carlson, a conservative who reportedly helped block former Secretary of State Mike Pompeo from getting a position in the new administration.

Mr. Cotton “has policy concerns with some of Elbridge Colby’s statements on our policy towards stopping Iran from getting a nuclear weapon,” one source close to the conservative lawmaker told Breitbart News. “Cotton has and is discussing with the White House.” Spokesmen for Mr. Cotton, chairman of the Senate Intelligence Committee, did not return an email request for comment on the nomination fight.

Mr. Colby has been criticized by some Middle East experts for suggesting that Iran developing nuclear weapons is less of a concern than dealing with China. Mr. Colby wrote in the past that containing a nuclear Iran is “eminently plausible and practical.”

Conservative China hands are concerned about Mr. Colby’s views regarding the Chinese Communist Party and the U.S. commitment to preventing a takeover of Taiwan by China.

He said in a 2022 speech that defending Taiwan from a Chinese attack is critical to the American strategy in Asia of containing Beijing. But he later stated the U.S. should “avoid unnecessarily poking Beijing” on Taiwan and instead should press Taipei to increase defense spending, a position Mr. Trump has advocated.

“The worst approach is upping the political temperature with Beijing with loud and symbolic measures vis-a-vis Taiwan while not prioritizing and enabling Taiwan’s laggardly defense efforts,” he stated on X.

Adm. Sam Paparo, commander of the Indo-Pacific Command, said in a speech last week that Chinese military maneuvers around Taiwan were not exercises but rehearsals for a future attack.

Mr. Colby has said he does not support policies that call for pushing back against Chinese provocations and aggression. His recent book, “The Strategy of Denial,” opposes the United States maintaining dominance in Asia to prevent a Chinese takeover of the region, and he argued that  American policy should form a regional coalition to prevent China from dominating regional states.

Mr. Colby also said he disagrees with China critics like Matthew Pottinger and former Rep. Michael Gallagher who stated in a recent journal article that the United States needs to go on the offensive and defeat China in global competition.

“We do not need their goal of full regime change and liberalization in China to achieve core American national interests vis-a-vis China,” Mr. Colby said on X. “Pursuing that goal against China greatly raises the risks of cataclysmic war, which we must try to avoid.”

Describing himself as a conservative realist, Mr. Colby favors detente with China despite it not being a final solution to the problem of Chinese global ambitions. An aggressive strategy of seeking to oust the Chinese Communist Party from power is too dangerous, he said.

Mr. Colby has his supporters in the Senate GOP ranks ahead of his confirmation battle.

Sen. Jim Banks said anyone who opposes the Colby nomination in the Senate is opposing Mr. Trump and the voters who elected him.

“The American people overwhelmingly rejected the status quo of America Last globalism by electing Donald Trump,” the Indiana Republican, told Breitbart News. “Under Elbridge Colby, the will of the American people will rightfully be at the center of our defense policy. Opposing Colby is opposing America’s best interests.”

• Bill Gertz can be reached at bgertz@washingtontimes.com.