WASHINGTON (AP) — In one of the most chilling scenes from the Jan. 6 insurrection, a violent mob surged through the halls of the U.S. Capitol chanting “hang Mike Pence.” But when the House moved this week to create an independent commission to investigate the tragedy, the former vice president’s brother voted no.

Pressed to explain his decision, Rep. Greg Pence of Indiana praised his brother as a “hero” and turned his ire on Democrats, calling the commission a “coverup about the failed Biden administration.” He was even more aggressive in a baseless statement labeling House Speaker Nancy Pelosi a “hanging judge” who “is hellbent on pushing her version of partisan justice complete with a hand-picked jury that will carry out her predetermined political execution of Donald Trump.”

Pence’s swift pivot to attacking Democrats and defending the former president about a riot that threatened his brother’s life is a stark measure of how the horror of Jan. 6 has been reduced from a violent assault on American democracy to a purely political fight.

Rather than uniting behind a bipartisan investigation like the ones that followed the 9/11 terror attacks, the assassination of President John F. Kennedy or Pearl Harbor, Republicans are calculating they can regain at least partial control of Congress if they put the issue behind them as quickly as possible without antagonizing Trump or his supporters.

“There’s no reason to be doing this,” said Sen. Rick Scott of Florida, who is leading the GOP’s efforts to win a Senate majority next year.

The Republican resistance to an independent commission comes as many in the GOP attempt to rewrite the history of Jan. 6, minimizing the haunting events of the day when a mob of Trump supporters used flagpoles as weapons and brutally beat police officers.

The issue could come to a head next week if the legislation creating the commission, which passed the House, gets a vote in the Senate. Democrats will need at least 10 Republicans to join them in backing the measure, a dim prospect after Senate GOP Leader Mitch McConnell expressed opposition this week.

The partisan fight over the new panel is alarming to historians who say an independent record of that dark day is needed to understand what happened and hold those involved accountable.

“If you don’t have follow-up, it reaffirms that folks are right in their wrongness,” said Carol Anderson, a professor of African American studies at Emory University.

The debate is unfolding as lawmakers prepare to spend much of the summer at home in their districts and attention gradually shifts to next year’s campaign. On the cusp of majorities in both chambers of Congress, Republicans are eager to make sure the races become a referendum on President Joe Biden — not their response to the insurrection.

“I want our midterm message to be about the kinds of issues that the American people are dealing with,” said Sen. John Thune of South Dakota. “It’s jobs and wages and the economy, national security, safe streets, strong borders and those types of issues, and not relitigating the 2020 election.”

That’s why even some of Trump’s most fervent critics in the GOP want to make sure that if a commission is formed, its work is done by the end of 2021 to avoid overlap with an election year, a provision included in the House legislation.

Without a firm deadline, the commission would be “a political event as opposed to a legitimate endeavor to determine how we can avoid attacks of this nature in the future,” said GOP Sen. Mitt Romney of Utah, who voted to convict Trump in both of his impeachment trials.

The 9/11 commission published its report in July 2004, just months before a presidential election, and included some criticisms of George W. Bush’s administration as the then-president was seeking reelection. But Romney said that was different because the 2001 terror attacks were not so directly linked to domestic politics, unlike the insurrection, which was led by Trump supporters seeking to block certification of Biden’s election victory.

“Clearly the people who attacked the Capitol were arguing for President Trump and therefore Republican,” Romney said. That leaves “the potential to have very significant political overtones in an election year.”

Lee Hamilton, the former Indiana Democratic congressman who co-chaired the 9/11 commission with Republican Tom Kean, the former governor of New Jersey, acknowledged that such investigations are inherently political because they are created by elected members of Congress. But he rejected firm deadlines, especially those created with upcoming elections in mind.

“You just have to take the time it requires,” he said. “If you have the right people, they’re going to do the right thing regardless of the political environment.”

The investigation of the insurrection would also be aided by the hundreds of prosecutions of rioters that are playing out in federal court, and the trail of evidence those proceedings lay out could hasten a commission investigation in ways not possible after 9/11.

The political environment, however, is much different now than it was when the 9/11 commission released its report. Trump insists the 2020 election was stolen, an argument roundly rejected by Republican election officials, dozens of federal judges and Trump’s own attorney general, William Barr.

Yet the lie is having an impact, with 70% of Republicans saying they don’t believe Biden legitimately won enough votes to be elected, according to a CNN poll released earlier this month.

The GOP insists it isn’t ignoring the attack, pointing to ongoing investigations by law enforcement and congressional committees. Trump and his senior aides, however, have not been interviewed by the congressional committees, meaning investigators have not been able to glean crucial information about the former president’s state of mind during crucial moments of the riot.

Sen. John Kennedy, Republican of Louisiana, said the public doesn’t need a commission to understand what happened at the Capitol and dismissed the idea that Republicans may pay a political price if they block the legislation.

“The American people are smart enough to figure out what’s going on,” he said.

That leaves Democrats, many of whom are astounded that such a violent attack on their workplace has devolved into a political brawl, grappling with how to proceed. Democratic pollster Geoff Garin acknowledged the attack may fade in the minds of many voters by the next election. But he said the party could make a bigger argument that Republicans are still doing the bidding of Trump.

“When Republicans behave in a way that shows they dance to whatever tune Trump happens to call, that is clearly damaging to the Republican Party brand,” he said.

Sen. Gary Peters of Michigan, who is leading Democrats in their effort to expand the Senate majority, said that if Republicans block the commission, it will send the message that “they are not interested in the truth.”

But Sen. Tim Kaine of Virginia, a former chair of the Democratic National Committee and the party’s 2016 vice presidential nominee, said the party should focus on its broader accomplishments, even if the push for an independent commission reaches a disappointing conclusion.

“Democrats are more likely to use, ‘hey we got the American rescue plan passed and vaccinations are proceeding at pace and Americans are living better and feeling happier and more economically prosperous,’” he said. “That the Republicans are still stuck in a fantasy land where they’re trying to whitewash history and pretend things didn’t happen that did, I think that could be a minor note.”