WASHINGTON — House Republicans rammed through a measure on Thursday opening a new investigation of the deadly assault in Benghazi, Libya, vowing to dig deeper in a search for truth. Democrats declared it merely a political ploy to raise campaign cash and motivate voters.
A bitterly divided House voted 232-186 to establish the panel that Speaker John A. Boehner insisted would answer questions that linger almost 20 months after the Sept. 11, 2012, attack on the US diplomatic mission. Seven Democrats, many facing tough re-election campaigns, broke ranks and joined Republicans in supporting the probe.
The panel’s investigation will be the eighth on Benghazi and will examine the entirety of the attack that killed US Ambassador J. Christopher Stevens and three other Americans. Independent, bipartisan, and GOP-led probes have faulted the State Department for inadequate security at the outpost, leading to four demotions. No attacker has yet been brought to justice.
Republicans say they are unsatisfied with explanations so far, and they have leveled a range of accusations against President Obama, former secretary of state Hillary Rodham Clinton, and other administration officials. Chief among them: that the administration misled the American people about the nature of the attack during a presidential election campaign and stonewalled congressional investigators.
‘‘We will not take any shortcuts to the truth, accountability, or justice,’’ Boehner said during House debate.
Democrats remain divided over whether to boycott the select committee. They are concerned that their participation would grant legitimacy to what they believe will be a partisan forum. But they also worry that if they avoid it they will not have the chance to counter GOP assertions and defend potential witnesses — including Clinton, a possible 2016 presidential candidate.
Party leaders will meet with their rank-and-file members Friday morning to decide on the next step.
Representative Ileana Ros-Lehtinen, Republican of Florida, criticized the ‘‘song and dance’’ she said came from Clinton when House members wanted to question her about Benghazi a few months after the attack. Clinton’s testimony before the House Foreign Affairs Committee was delayed when she missed a month of work toward the end of her tenure after suffering a virus, then a fall and a concussion, and then brief hospitalization for a blood clot near her brain.
Representative Louise Slaughter, Democrat of New York, said no evidence uncovered in any of the investigations thus far suggests wrongdoing by the administration. Republican assertions have descended into ‘‘the crass and unbelievable,” she said.
Benghazi has produced 13 public hearings, the release of 25,000 pages of documents, and 50 separate briefings.
The select committee won’t be the only inquiry, as other GOP-led congressional panels continue their probes, including a House Oversight investigation which just last week took the extraordinary step of subpoenaing a Cabinet member. Secretary of State John Kerry has not said when he might testify.
Democrats deride the effort as a conservative campaign designed to energize Republican voters in typically low-turnout midterm elections.
Boehner’s legislation creates a select House committee through the end of the year. It will have to be reapproved when a new Congress begins in January or go out of existence. The select committee has no explicit financial constraints.
Earlier this week, the National Republican Congressional Committee sent an e-mail vowing that ‘‘no one will get away’’ from the committee’s investigation and asking people for donations.
Representative Steve Israel of New York, the Democratic campaign committee chairman, called fund-raising off Benghazi ‘‘despicable and insulting.’’ Boehner on Thursday refused to criticize the fund-raising drive.
In an opinion piece Thursday in USA Today, the congressman whom Boehner has chosen to head the probe signaled he’d reexamine the entirety of the Benghazi attack, including questions Democrats and some senior Republicans consider settled.
The GOP-led House Armed Services Committee concluded months ago the US military could not have responded in time to save Stevens and the others. Still, Representative Trey Gowdy of South Carolina asked: ‘‘Was our military response during the pendency of the siege sufficient?’’
The Obama administration says officials tried to provide the public with the best information available after the attack at a time when US embassies, consulates, and other facilities were facing angry demonstrations across the Muslim world over a YouTube video mocking Islam’s Prophet Mohammed. The administration originally attributed Benghazi to a similar protest that extremists hijacked, but retracted that account.
House Democrats have issued several demands if they are to participate in the select committee. Boehner already has rejected their call for equal representation on the panel, deciding instead to fill it with seven Republicans and five Democrats. The Democrats also seek equal access to documents, a say on subpoenas, and right to question witnesses. Negotiations continue.