(CNN) - The No. 2 House Democrat harshly criticized House Speaker John Boehner’s decision to move forward with a select committee to investigate the deadly Benghazi terror attack, and said Democrats haven’t decided if they’ll participate.
"We think this is a political, not a substantive effort," Rep. Steny Hoyer of Maryland told reporters on Monday about the new panel to probe the armed assault in September 2012 that killed four Americans, including Ambassador Christopher Stevens.
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Hoyer said he would urge all fellow Democrats to vote against the bill creating the panel that’s expected to be on the floor as early as this week.
The GOP-led House is expected to approve it, but it’s possible Democrats could boycott the investigation.
Boehner said South Carolina Republican Rep. Trey Gowdy, a former federal prosecutor, would chair the committee. But Democrats have not received any details on its structure, funding or powers.
House Democratic leaders want more information before deciding how they would respond.
"If they (Republicans) want to have a substantive effort, it ought to be an equally balanced committee so this is not an exercise in partisanship. But we'll see whether that's the case,” Hoyer said.
Benghazi has become a political flashpoint in Washington and a rallying cry for Republican critics of President Barack Obama’s conduct of foreign policy.
Republicans have focused on the U.S. security posture before the attack in eastern Libya, the official response during the assault, and the Obama administration’s slow-to-evolve explanation of what occurred once it was over.
The issue boiled over in 2013, but had been simmering this year until new documents surfaced last week that prompted renewed GOP claims the administration politicized its public explanation of events in the days after the attack.
The White House said the new development was unrelated to Benghazi.
One senior House Democratic leadership aide echoed Hoyer's call for a 50/50 split among GOP and Democratic lawmakers.
The aide noted criticism Democrats raised in 2005 when Republicans formed an investigative panel to study the response to Hurricane Katrina and gave more slots to GOP members. At that time House Democratic Leader Nancy Pelosi refused to appoint Democratic members.
Democrats also want to know whether Gowdy will be able to unilaterally issue subpoenas, or whether the panel would be required to have a majority vote before demanding new testimony or materials.
On Sunday Rep. Adam Schiff, a senior Democrat on the House Intelligence Committee, called the Benghazi select committee “a colossal waste of time, saying the House already had four investigations.
“I don't think it makes sense really for Democrats to participate. I think it's just a tremendous red herring and a waste of taxpayer resources,” Schiff said on Fox News.
Hoyer read quotes from Boehner in April when he said he opposed the creation of such a panel.
The "political pressure of the base" made the speaker change his mind, Hoyer said. He said he didn’t believe the panel would reveal any new information.
Hoyer raised a question for GOP leaders about Oversight Committee Chairman Darrell Issa, whose panel has taken the lead in investigating Benghazi.
"Either they think Mr. Issa is a competent chairman and is pursuing a competent investigation or they don't," Hoyer said.
Hoyer said Issa already had subpoena power to obtain testimony and documents, held "numerous hearings" and has found "no smoking gun, no wrongdoing."