A week ago, reveling in the attention, Mitt Romney’s presidential campaign was delighted to highlight the Obama campaign’s criticisms of the former governor. Romney’s team even put together a video, streaming together Democratic criticism of the Republican candidate, with a one-word title: “Nervous?

This week, one might be inclined to ask Romney’s campaign the same question.

For months, if not years, the former governor has focused all of his energy on going after the president. Romney was largely content to pretend he had no primary rivals, and looked to already be gearing up for the general election. Just over the last few days, however, Romney has decided to engage the other Republican candidates in ways unseen all year.

In the CNN debate, for example, we saw Romney go after Herman Cain’s tax plan and challenge Newt Gingrich over health care mandates. Yesterday, the Romney campaign went much further, releasing a video suggesting Rick Perry is a bit of dolt.

As it turns out, a few hours later, Romney’s team pulled the minute-long clip without explanation, but American Bridge grabbed a copy and posted it this morning*.

Nate Silver noted last night, “Romney’s new attack ad is the sort of thing a campaign puts out when it thinks it lost a debate.” That’s exactly right.

This comes, by the way, a day after Romney’s team used some pretty harsh language to describe the Texas governor to reporters.

Romney adviser Ron Kaufman called Perry “a petulant little boy” and said that Romney “put him in his place.”

“The governor of Texas came across as mean, petulant and nasty,” Kaufman said.

This is, as a strategic matter, bizarre. Perry has seen his support fall off a cliff in recent weeks, whereas Romney is considered the likely GOP nominee. By attacking Perry directly and aggressively — instead of simply ignoring a candidate who appears to be imploding all on his own — the Romney camp isn’t even trying to hide the fact that it considers the Texas governor a serious threat.

Most campaign observers believe there’s one credible candidate standing between Mitt Romney and the Republican nomination, and that’s Rick Perry. Yesterday, whether they meant to or not, Romney and his team dropped the pretense and made clear they accept the conventional wisdom as fact.

It’s the sort of thing that, ironically, might give Perry’s flailing effort a shot in the arm.

* updated

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.