All three were focusing attention on the vote last year by their competitors to create a bipartisan “National Commission” to investigate the Jan. 6, 2021, attack on the U.S. Capitol, which was done by a pro-Trump mob. Such criticism has put dozens of House Republicans on the defensive in this year’s primaries, forcing them to fend off condemnations from challengers who are using the vote to argue that the incumbents aren’t conservative enough, even though the commission, as specified in legislation, was never approved by the full Congress, much less assembled.

The prevalence of the criticism reflects the unease some Republicans have sensed among GOP base voters about the House select committee currently investigating the Jan. 6 attack, which held its latest public hearing Thursday. Even though only two Republicans — Reps. Liz Cheney (Wyo.) and Adam Kinzinger (Ill.), who now sit on the panel — voted to create it, after the previous proposal failed in the Senate, many conservative candidates are zeroing in on the earlier vote for a commission as they try to tap into anger over the proceedings.

The next test of these political fault lines comes Tuesday, when five of the 35 House Republicans who voted for the commission will be on the ballot. So far, 12 have won or advanced from their primaries. Two have lost. Nine others retired or resigned.