Donald Trump has set the tone: Republicans are supposed to attack anyone who serves as a witness in the impeachment inquiry. Trump attacked Ambassador Marie Yovanovitch while she was testifying. He attacked Jennifer Williams, a Mike Pence aide who is testifying Tuesday. And Republicans have already gotten the message about attacking Lt. Col. Alexander Vindman, who is also testifying Tuesday.

On Monday, Sen. Ron Johnson described Vindman as part of a “deep state” who “never accepted President Trump as legitimate.” This followed a series of attacks on Vindman, to the point where the Army is making plans to move him and his family to a military base if they appear to be in danger.

On Tuesday, as Vindman and Williams testify in the morning and former special envoy to Ukraine Kurt Volker and National Security Counsel official Tim Morrison testify in the afternoon, which member of Team Trump will lob the most outrageous attack? Will it be Trump himself, as with Yovanovitch and Williams? Will it be Don Jr., who tweeted Friday, “America hired [Trump] to fire people like the first three witnesses we’ve seen”? You know, highly qualified diplomats who’ve served the U.S. under multiple presidents. Or will it be a House Republican like Jim Jordan or Lee Zeldin? Whichever high-profile Republican makes the initial attack, it will be endlessly amplified by Fox News and the rest of the far-right media.