The traitorous invasion of the U.S. Capitol on Jan. 6 led to five deaths, including that of Capitol Police Officer Brian Sicknick, who died of natural causes the day after clashing with the crowd. Damages to the Capitol at last count topped $30 million. Expenses to maintain Guard troops and impose other security measures have cost nearly half a billion dollars. Worst of all, the invasion shattered any illusions that this citadel of democracy was somehow immune to the ravages of a mob.

Watching hundreds of insurrectionists breach what should have been a secured perimeter, scale the walls of the Capitol itself and break windows to gain entry and attempt to block the certification of a presidential vote was a sight that will — and should — haunt many Americans.

For all those reasons, it is imperative that the House and Senate, Democrats and Republicans, join together to determine how those events unfolded. Sadly, little conveys the dysfunctional state of our democracy more than the shameful recent move by Senate Republicans to block the creation of a bipartisan, 9/11-style commission.

Rep. Tom Emmer, R-Minn., who, along with every other member of Minnesota's Republican delegation, voted against the commission in the House, said in a statement, "Adding another commission does nothing to help the American people move forward or bridge the current political divide in our country."

That is simply untrue. Few know better than U.S. Sen. Amy Klobuchar, D-Minn., just how much such a commission is needed. Klobuchar has been working for four months with Sen. Roy Blunt, R-Mo., to study what led to the riot and what can be done to prevent a recurrence. That effort should not take the place of a full, detailed investigation that includes subpoena powers. Klobuchar, a former prosecutor, said the investigation underway by the Justice Department also has a specific focus: prosecuting individuals.

"This was an attack on our democracy," she said. "You need a commission because you need to make a thorough review of what happened. We need the credibility that comes with a bicameral, bipartisan commission, the experts that can look at all of this. We never want this to happen again, and we still have people denying it happened at all." It is precisely what is needed to "help the American people move forward."

This wasn't just some rally that went off the rails, despite the lies some are telling about events that day. There were those in the crowd who came fully prepared to commit mayhem, to act in concert to disrupt the certification of the Electoral College vote. That included building a makeshift gallows outside and shouting "Hang Mike Pence" while those inside hunted the vice president and actually came within 100 feet of him before a courageous Capitol Police officer drew the mob in another direction.

This was an hourslong assault that brought the mob to the very chamber doors of the House. We have too few answers still about how the events of that day unfolded, who planned them, who funded them, who helped and why the Capitol was so underprotected.

The recommendations from Klobuchar and Blunt's committee will shed some light on what actions to take next. But as Klobuchar noted, "my group only involves four senators." Nevertheless, it will be the first bipartisan review, with recommendations to be released next week.

In the meantime, she said of a 9/11-style commission, "I think we should have another Senate vote. We came very close in the last vote, and there are Republicans that will vote for it that were missing."

This is important enough to bring up for a vote as many times as it takes. The peaceful transfer of power is at the heart of this democracy. It nearly didn't happen this time. We dare not risk a repeat because we refused to learn all that we could about Jan. 6.