After some moments of confusion — how appropriate for a campaign that can’t shoot straight — Texas Gov. Rick Perry decided he will stay in to fight in South Carolina. The Texas Tribune reports:

Despite a disappointing fifth place finish in Tuesday night’s Iowa caucuses that led Rick Perry to say he was returning home to Texas to reassess his candidacy, the Texas governor surprised everyone — including some of his own staff — by tweeting that he was headed to the Palmetto State.

“Next leg of the marathon is the Palmetto State,” Perry tweeted, posting a picture of himself in jogging gear giving a thumbs up. “Here we come South Carolina!!!”

Perry’s son Griffin Perry followed up with his own tweet confirming his father’s intentions. “See y’all next week in Carolina! I expect all my SEC brethren to come out in force,” the younger Perry tweeted.

The Mitt Romney camp is certainly celebrating that development, as a divided field in South Carolina will make it that much more likely that he will cruise to victory. With Newt Gingrich, Rick Santorum, Rep. Ron Paul (R-Tex.) and now Rick Perry vowing to fight it out among themselves, Romney is in precisely the same position as Sen. John McCain (R-Ariz.) was in 2008. In short, he can sew up the nomination by getting about 30 percent of the vote in South Carolina.

The Romney camp was already relieved today, grateful that the potent Newt Gingrich and well-funded Perry flopped in Iowa and that Paul doesn’t come into New Hampshire with a head of steam. As for Santorum, Romney senior advisor Stuart Stevens was careful to indicate that the Romney camp isn’t taking him lightly. He told me over the phone that Santorum deserves credit for doing so well in Iowa. “He earned it. He is a person deserving of respect.”

It’s clear the candidates remaining in the field will come after Romney hammer and tongs. But it is far from clear whether he’ll have to take on Santorum. Initially, he no doubt will rely on the other candidates and the media to vet Santorum. He’s a trickier opponent for Romney, someone whose personal qualities are above reproach, who can articulate his views and whose record places him squarely in the conservative movement.

However, Romney’s great advantage from the beginning has been his steadiness and ability to outlast flawed opponents. The decision by Perry, to the chagrin of many in the base, will likely be a significant boost to his prospects for winning the nomination.