Sen. Mark Warner works with staff on Capitol Hill in Washington on Nov. 19. (Melina Mara/The Washington Post)

Holiday timing and policy concerns helped delay a leadership post awarded to Sen. Mark R. Warner (D-Va.) late last week.

Senate Democrats announced Friday that Warner would be named policy development adviser at the Democratic Policy and Communications Center, an advisory group led by Sen. Chuck E. Schumer (N.Y.).

Sen. Elizabeth Warren (D-Mass.) had been elevated to a similar post to great fanfare two weeks earlier. While Warner’s promotion was announced far more quietly, aides said it had been in the works since a three-hour post-election caucus meeting at which several moderate Democrats did not vote for Majority Leader Harry M. Reid (Nev.).

Warner’s office said the leadership announcement was delayed by his desire for assurance that he still would be able to challenge Democratic leadership and form “gangs” with Republicans on various issues. After his narrow reelection, Warner promised to be more of a “disrupter” in office. He was among the senators who voiced opposition to Reid’s leadership.

Moderate Democrats were pleased to see Warner elevated, even with a muted announcement the day after a holiday.

“We know he will be a great voice for business,” said Sen. Heidi Heitkamp (N.D.).

But some liberal observers saw the move as a sign that the party was betraying them.

“The Warren wing of the party may be exceedingly passionate and engaged, but let’s not delude ourselves into thinking that it’s carrying the day,” wrote Salon’s Luke Brinker. A blogger at the liberal Daily Kos called Warner a “Wall Street shill, and right-wing defector.”

Leadership at the top of the Democratic caucus has not changed after an election in which the party lost eight Senate seats. Instead, the team has been expanded to include not just Warren and Warner but Jon Tester, from the red state of Montana, and Amy Klobuchar, from the blue state of Minnesota.

“The thing that leadership has done very well is Warner, Tester, Klobuchar, Warren, adding them, adding that to the leadership team,” said Warner’s fellow Democratic senator from Virginia, Timothy M. Kaine, though he added that he did not see it as a matter of balancing ideologies.

In fact, while they may represent different sides of the party, Warner and Warren are hardly enemies. A prodigious fundraiser, Warren raised money for her colleague in the last election, and the two recently teamed up to urge action on housing finance reform.