WASHINGTON — A third House committee joined the stampede to examine the IRS on Monday, and its chairman did exactly what you would expect somebody to do before launching a fair and impartial investigation: He went on Fox News Channel and implicated the White House.

Asked by Fox’s Bill Hemmer what he hoped to learn at Monday afternoon’s hearing, Appropriations Committee Chairman Hal Rogers, R-Ky., offered this bit of pre-hearing analysis:

“Of course, the enemies list out of the White House that IRS was engaged in shutting down or trying to shut down the conservative political viewpoint across the country — an enemies list that rivals that of another president some time ago.”

It was a sentence in need of a verb but packed with innuendo. And it is part of an approach by House Republicans that seems to follow the Lewis Carroll school of jurisprudence. Not only are they placing the sentence before the verdict, they’re putting the verdict before the trial.

Rep. Darrell Issa, R-Calif., chairman of the House Oversight Committee, announced his conclusions on CNN Sunday, declaring White House press secretary Jay Carney a “paid liar” for saying that the targeting of conservative groups was the work of a “rogue” element operating out of the IRS’ Cincinnati office. “The reason that Lois Lerner tried to take the fifth is not because there is a rogue in Cincinnati,” Issa told reporter Candy Crowley. “It’s because this is a problem that was coordinated in all likelihood right out of Washington headquarters and we’re getting to proving it.”

Getting to proving it?

Congressional investigators have not produced evidence to link the harassment of conservative groups to the White House or to higher-ups in the Obama administration. But the lack of evidence that any political appointee was involved hasn’t stopped the lawmakers from assuming that it simply must be true. And so, they are going to hold hearings until they confirm their conclusions.

Monday afternoon’s IRS hearing was held by the Appropriations Committee. Judging from the less-than-capacity crowd, public enthusiasm for the inquiries is waning. But for those who missed that hearing, another was scheduled on Tuesday morning so the Ways and Means Committee could take shots at the agency. On Thursday, Issa’s committee meets yet again to discuss the topic.

The lawmaker holding the gavel at Monday’s hearing, Rep. Ander Crenshaw, R-Fla., chairman of the Appropriations subcommittee on financial services, preceded his official duties by going on Fox News a few hours after Rogers. Crenshaw told Fox that “instructions on who to target and how to target were coming from Washington without any debate.”

Actually, that’s a matter of considerable dispute. IRS officials in Washington and elsewhere were indeed involved in targeting conservative groups. But it’s quite another thing to say that Washington was leading the effort or suggest that any presidential appointee was involved. Perhaps investigators will eventually uncover evidence of such a thing. But to announce their conclusions before assembling the facts helps the Obama administration make a case that the inquiries are partisan.

At Monday’s hearing, Rogers attempted to link President Obama to the scandal at what he called “allegedly an independent agency” by asking whether the president had approved bonuses for “these very critical people in this scandal.” In the absence of facts, Rogers said it just “doesn’t make sense” that the IRS targeting was not “directed from on high.”

Rep. Tom Graves, R-Ga., accusingly asked the witness, new IRS chief Danny Werfel, if he had met “with anyone from the White House to prepare for” the hearing. He hadn’t. Graves also found suspicious the fact that Werfel has “yet to even go to Cincinnati” to investigate. Werfel has been on the job 12 days.

Rep. Steve Womack, R-Ark., tried to run down a theory that the White House had told Werfel to “take any potential consequences off the table.” And Rep. Kevin Yoder, R-Kan., proposed that IRS civil servants were being used as “scapegoats” by Obama’s political appointees.

The Republicans seemed not to care that the other witness at the hearing, IRS Inspector General J. Russell George, told the committee that he had no evidence that anybody from the White House or any presidential political appointee was involved.

Graves pressed ahead with his belief that “the president or subordinates of the president were well aware of or involved in the targeting of political opponents.” Like his colleagues, he was not about to let the rude intrusion of contrary evidence disturb his conclusion.

Dana Milbank is a Washington Post columnist.