Democrats are denouncing the House GOP investigation into the weaponization of government, but maybe that’s because Republicans are getting somewhere. That includes new evidence that the Internal Revenue Service may be targeting a journalist who testified before the weaponization committee.

House Judiciary Chairman Jim Jordan sent a letter Monday to IRS Commissioner Daniel Werfel and Treasury Secretary Janet Yellen seeking an explanation for why journalist Matt Taibbi received an unannounced home visit from an IRS agent. We’ve seen the letter, and both the circumstances and timing of the IRS focus on this journalist raise serious questions.

Mr. Taibbi has provoked the ire of Democrats and other journalists for his role in researching Twitter records and then releasing internal communications from the social-media giant that expose its censorship and its contacts with government officials. This effort has already inspired government bullying, with Chair Lina Khan’s Federal Trade Commission targeting new Twitter owner Elon Musk and demanding the company “identify all journalists” granted access to the Twitter files.

Now Mr. Taibbi has told Mr. Jordan’s committee that an IRS agent showed up at his personal residence in New Jersey on March 9. That happens to be the same day Mr. Taibbi testified before the Select Subcommittee on the Weaponization of the Federal Government about what he learned about Twitter. The taxman left a note instructing Mr. Taibbi to call the IRS four days later. Mr. Taibbi was told in a call with the agent that both his 2018 and 2021 tax returns had been rejected owing to concerns over identity theft.