Congress has done an admirable job conducting oversight hearings about the Jan. 6 attack on the U.S. Capitol. Still, the latest threats of violence reported by the U.S. intelligence community portray a clear and present danger, combined with our hyper-partisan politics, lead to a combustible cocktail of problems and reinforce my belief that we must do more to address this.

As a former member of Congress who helped write the legislation creating the 9/11 Commission with the late Sen. John McCain (R-AZ) and a member of that historic Commission, it is clear to me our country needs a similar nonpartisan commission of highly respected civilians to investigate the deadly events of Jan. 6, determine what causes led to this violence, understand the rise of domestic terrorism, and make recommendations to strengthen our representative democracy.

If the events of Jan. 6 taught us anything, it’s that we must treat domestic terrorism as seriously as we do foreign terrorism.

Such a commission must address intelligence failures, security lapses, and who exactly participated in this violence. But it would be a mistake for it to focus singularly on how high to build walls and how many additional security personnel to recruit. This must also be about the dangerous forces in America that caused the carnage we all watched unfold in real-time as our constitutional process of peacefully transferring power was suddenly disrupted.

FBI Director Christopher Wray recently testified that domestic terrorist groups are “metastasizing across the country.” And in a troubling new report from the U.S. intelligence community, domestic extremists feel emboldened in the wake of Jan. 6 and continue to be motivated by conspiracy theories. As we learned through our work on the 9/11 Commission, the attacks on Sept. 11 were neither completely unpredictable nor, with the exception of their scope and scale, truly unprecedented. The trail of breadcrumbs existed—the August 1998 bombings of U.S. embassies in Kenya and Tanzania, and the October 2000 bombing of the USS Cole in Yemen. Yet it wasn’t until after Sept. 11 that we were truly able to connect the dots. Let’s not make the same mistake again.

The scope of this investigation must be clearly defined and the commission must be appropriately empowered. Ensure access to relevant information and subpoena power. Give it independence and supply it with sufficient resources. Make certain it has skilled and nonpartisan staff. And it is crucial that the right people are appointed commissioners—women and men who will follow the facts and put country before party. Patriots who will inspire the country by the rigor of their investigation and wisdom of their recommendations. This can solely determine its success or failure.

Speaker Nancy Pelosi (D-CA) has already started working on legislation to create a Jan. 6 commission. It should reflect the composition of the 9/11 Commission and be evenly divided 5-5 between Republicans and Democrats. Similarly, the commission chair would also be selected by the president.

While Pelosi and Senate Majority Leader Chuck Schumer (D-NY) would each appoint two members of the commission, so too would House Minority Leader Kevin McCarthy (R-CA) and Senate Minority Leader Mitch McConnell (R-KY). Every one of these members were inside the Capitol as domestic terrorists infiltrated its storied halls. And as such, they must work together to ensure such atrocities never happen again.

In Pericles’ famous funeral oration, a speech given to honor fallen Athenian heroes at the end of the first year of the Peloponnesian War, he praised the values of honor, freedom, courage, liberty, and justice. These are many of the distinctive traits required by leaders in free societies to take necessary action. As they negotiate and build toward a Jan. 6 commission, we are strongly encouraging our leaders in Congress to invoke honor and courage by putting partisan differences aside. We are counting on them to protect our freedom and liberty by exposing the root causes that led to the siege of one of our nation’s most symbolic buildings and an overt attempt to overthrow our democracy.

Though we failed to heed the warning signs that preceded  Sept. 11, we have an opportunity to be proactive now to prevent further deadly attacks on our soil. And a clear and present threat to America is inside our country. A thorough, nonpartisan, impartial, and independent Jan. 6 Commission is our best hope to end that trajectory before more American lives are lost. Our representative democracy is vulnerable, and we must work together to repair it.