Mark Esper's comments came after Trump said that he believed four U.S. embassies would have been attacked if Soleimani was not killed.
Mark Esper said in October that the Department of Defense "do everything we can" to comply with the impeachment inquiry.
The singer made the remark after Navy Secretary Richard Spencer said he does not share the same view of "good order and discipline" with the president.
"As with Patrick Shanahan, Mark Esper's appointment as acting Secretary of Defense brings up questions regarding potential conflicts of interest," Rachel Rizzo, of New American Security, told Newsweek.
"I have to have confidence that the fox is not going to be put back into the henhouse," McCain told Shanahan. He suggested that placing an executive from one of the largest military defense contractors, a man with no prior military experience, in such a powerful Pentagon role could be damaging to the agency.
Donald Trump's choice for secretary of defense is 'not a fool or a cowboy' and could actually be a calming influence on the administration.
He initially shared his decision with his supporters via email.
Pentagon could change policy that punished medical personnel for objecting to the procedure.
His administration is fighting to keep 2,000-plus images from the public.
But Obama did initially hire him for his candor…what did he expect?