Marco Rubio successfully evaded financial questions at the third G.O.P. Presidential debate by making accusations of media bias. PHOTOGRAPH BY ROBYN BECK / AFP / GETTY

The big post-debate story is about the media. CNBC is being pilloried by Republicans for the way it conducted last night’s event, in Boulder, Colorado. “CNBC should be ashamed of themselves,” Reince Priebus, the chairman of the Republican National Committee, wrote in an e-mail to supporters. “Let's put the mainstream media on notice. I want to send a message to moderators of upcoming debates that any bias won’t be tolerated.” Rand Paul, who was once the darling of the mainstream media and celebrated as a top-tier Republican candidate, but who has been a non-entity in the Presidential campaign, used the anti-CNBC backlash to raise money. He changed his Twitter avatar to a picture of the senator with a black rectangle over his mouth and the word CENSORED across it. “Fight back against the media bias” was superimposed on the new photo.

Whining about tough questions and media bias is an old campaign tactic. On both the right and the left, there are now well-funded institutions that do nothing but scour the Internet, TV, and radio for perceived slights from the press. The CNBC journalists are public figures who surely know that getting beaten up by partisans comes with the job of covering American politics. And, of course, just because accusations of bias or unfairness come from the R.N.C. and the G.O.P. Presidential candidates, who all have strategic reasons for attacking the press, doesn’t mean that they are untrue.

But, as last night’s debate went on and the candidates realized that the crowd had turned against the moderators, and that they could score easy points by lambasting them, legitimate grumbling about some tough questions turned into something else: using the charge of media bias to avoid answering legitimate questions. The candidate who pulled this off better than anyone was Marco Rubio, who was generally seen as the winner of the debate.

Becky Quick, a CNBC correspondent, asked Rubio the following question:

Senator Rubio, you yourself have said that you’ve had issues. You have a lack of bookkeeping skills. You accidentally intermingled campaign money with your personal money. You faced foreclosure on a second home that you bought. And just last year you liquidated a sixty-eight-thousand-dollar retirement fund. That’s something that cost you thousands of dollars in taxes and penalties. In terms of all of that, it raises the question whether you have the maturity and wisdom to lead this seventeen-trillion-dollar economy. What do you say?

This was as predictable a question as Rubio could expect. His personal finances have been raised as an issue for years. In his own memoir, Rubio wrote about the troubles he had mixing personal and business purchases on a Republican Party credit card, and lamented his “lack of bookkeeping skills.”

But Rubio decided that the question was hostile and that he could therefore evade it. “You just listed a litany of discredited attacks from Democrats and my political opponents,” he said, as if that proved the accusations were false, “and I’m not gonna waste sixty seconds detailing them all.”

Quick’s questions were cited by several conservative commentators after the debate as being unfair. Several argued that Democrats were not asked similarly tough questions in the recent CNN debate. That’s silly.

The first question of the Democratic debate, for Hillary Clinton, was “Will you say anything to get elected?”

Rubio, clearly feeling how the room had turned against the moderators, came back a little later in the debate and delivered one of the big applause lines of the night: “I know the Democrats have the ultimate super PAC. It's called the mainstream media.”

Not a bad line. But Rubio must know that the issue of his finances isn’t going away. The Miami Herald has reported that Rubio “amended his financial disclosure forms … after The Miami Herald asked why they lacked a $135,000 home equity loan he obtained from a bank controlled by his political supporters.” The Tampa Bay Times has reported that Rubio “double-billed the Republican Party of Florida and state taxpayers for eight flights while he was House Speaker.” (He said that was a mistake, and that he would repay the party.) The Times also reported that “Rubio billed the party for more than $100,000 during the two years he served as the state's House speaker,” and that “charges included repairs to the family minivan, grocery bills, plane tickets for his wife, and purchases from retailers ranging from a wine store near his home to Apple's online store.” (Rubio said that the expenses were all related to party business.)

Rubio is about to go through a period of much more intensive media scrutiny. Complaining about media bias won’t be enough to get him through it.