Establishing a select committee to investigate the State Department's handling of the 2012 attack on a U.S. diplomatic outpost in Libya is a "colossal waste of time," according to Rep. Adam B. Schiff (D-Calif.).

"We've had four bipartisan investigations already," Schiff said on "Fox News Sunday," adding that the Republican plans to create the committee are politically motivated. 

Schiff also said that Democratic leaders should not appoint anyone to the committee. "I don't think it makes sense, really, for Democrats to participate," he said. "I think it's just a tremendous red herring and a waste of taxpayer resources."

National security adviser Susan E. Rice with Treasury Secretary Jack Lew (Kevin Lamarque/Reuters)

Republicans called for the select committee last week after the court-ordered release of a memo from White House adviser Ben Rhodes recommending that Susan E. Rice, who was then the U.S. ambassador to the United Nations, should "underscore that these protests are rooted in an internet video, and not a broader failure of policy."

Sen. Kelly Ayotte (R-N.H.) said Sunday that the White House had been pushing a political explanation for the attack in order to protect President Obama's reputation during the 2012 election.

Schiff echoed comments this week from White House press secretary Jay Carney, who said the memo was not specifically about Benghazi even though it contained some references to the attack in the eastern Libyan city.

Ayotte said that explanation "doesn't pass the laugh test."