Start by taking dissident Republicans at their word that Donald Trump’s Big Lie undermined our democracy, disrupted the peaceful transfer of power, and inspired the insurrection. These admissions by top Republicans will stain the former president and his political movement.

But it shouldn’t end there.

Democrats and pro-democracy Republicans should take an aggressive posture on witnesses for the 9/11 Commission-style investigation into the storming of the Capitol. Liz Cheney is right that the probe should be led by former officials, people uncompromised by threats of primary challenges or political retribution.

The power to issue subpoenas, and enforce them, will also be critical. Michael Flynn should be called to testify—do it in prime time—about his advocacy for martial law and his support for a pro-insurrection militia group.