The Senate did not have to confirm McMaster to lead the White House's National Security Council, but the law requires the Senate to confirm three- and four-star generals when they change jobs.

Ahead of the vote on Wednesday, Senate Armed Services Committee Chairman Sen. John McCain, R-Ariz., urged his colleagues to approve McMaster with brief remarks on the Senate floor.

"He is experienced, talented, and he knows what it's like to be in combat with the enemy, and I believe he is badly needed in this important position," McCain said.

Senate Minority Leader Chuck Schumer, D-N.Y., was among the 10 Democrats who voted no, a list that included more than half of SASC Democrats: Sens. Kristen Gillibrand, of New York; Mazie Hirono, of Hawaii, Claire McCaskill, of Missouri, and Elizabeth Warren, of Massachusetts. Sens. Corey Booker, of New Jersey; Kamila Harris, of California; Ed Markey, Massachusetts; Jeff Merkeley, Oregon, and Bernie Sanders, of Vermont, were the others. 

In a floor speech before the vote, Schumer said the NSC had faced unprecedented turmoil, with the resignation of National Security Advisor Mike Flynn and inclusion of political strategist Steve Bannon — and expressed hope McMaster would be a "grounding presence."

"I have a great deal of respect for both his integrity and his abilities. But I remain deeply concerned that Gen. McMaster's judgment may not be followed and instead the fevered dreams of Mr. Bannon will influence the most sensitive national security discussions and decisions," Schumer said.