Mitt Romney must have spent a lot of time over the weekend practicing in front of the mirror.

After last week’s disastrous debates, you would have been forgiven for thinking Romney was the least electable candidate in the race. He stuttered line after line in an awkward staccato, bizarrely dwelling on his refusal to release his tax forms and giving Newt Gingrich’s bombast free rein.

A week later, Romney was all business. First thing at Monday night’s debate, he aggressively critiqued Gingrich’s record — so checkered that Romney even had the luxury of allowing himself more factual accuracy than the average political attack. Romney snappily compared Gingrich’s past with his own, beginning with Romney’s first job in business, taken at the same time Gingrich entered Congress decades ago. Then the former speaker resigned his perch “in disgrace” in 1998. Then Gingrich engaged in “influence peddling” for Freddie Mac. Then Gingrich sat on a couch with Nancy Pelosi and argued for cap-and-trade. (The last was actually an extremely good thing for which Gingrich deserves credit — but few Republicans will see it that way.)

Gingrich tried to counter-attack, saying that Romney’s charges were false, that Romney was bringing the race into the gutter, that he resigned the speakership in 1998 to save the GOP from partisan Democratic attacks. But then Ron Paul matter-of-factly ridiculed Gingrich, attesting that “the House was chaotic” when Paul got there in 1996, and that Gingrich didn’t have the votes to keep his job in 1998 — he didn’t voluntarily resign. If you can count on Paul for anything, it’s that he will tell you exactly what he thinks whenever he happens to think it, so that hurt.

Most importantly, Romney’s voice didn’t sound like a fish drowning in air. He seemed much more confident, no matter how calculated his new approach probably was. The fact that NBC had told the live audience to be docile no doubt helped. Gingrich shone last week when he riled up boisterous crowds of Southern Republicans with cynical applause lines; Romney wilted. Not so Monday night.

There were also a couple other people on stage, of course. But neither Paul nor Rick Santorum got to talk for the first 10 minutes of the broadcast, which is about how the rest of the debate went for them.

There’s still a more-than-negligible chance Romney’s negativity will backfire, as it did when he too-aggressively attacked his rivals in the 2008 GOP race. Gingrich’s relative restraint in the face of Romney’s attacks could help with that. Even if it doesn’t, nothing Romney did Monday night was nearly as dramatic as Gingrich’s standing-ovation lines in previous matches; the latest debate won’t be as effective at stopping Gingrich’s momentum as last week’s were at creating it.

But Romney was back in form on Monday — despite his deficiencies as a candidate, he still seemed like the most likely president on stage. That shouldn’t, however, be hard. Gingrich has a barn’s worth of baggage; beating the former speaker should be as easy as hitting the door. President Obama will be a much more formidable opponent.

More on the Florida debate from PostOpinions

Bernstein: An awful night for Gingrich

Rubin: Gingrich falters without a cheering section

Petri: Romney and self-deportation time