Hours before the polls closed in Alabama and Mississippi's Republican presidential primaries on Tuesday, Mitt Romney suggested on CNN that Rick Santorum "is at the desperate end of his campaign." The voters apparently disagreed. Defying the polls and expectations, Santorum scored narrow but narrative-changing upsets in both Deep South states, beating Romney and Newt Gingrich by about 5 percentage points in Alabama and 2 points in Mississippi. Romney won the night's other two contests, caucuses in Hawaii and American Samoa. Here, a look at what Santorum's Southern sweep means for the GOP contest:

1. Santorum just made this a real race
These wins mark "a breakthrough moment for Santorum," says Howard Kurtz at The Daily Beast. Romney heavily outspent him, and scored endorsements from everyone from Mississippi's governor to comedian Jeff Foxworthy. In true "David vs. Goliath" style, Santorum overcame those obstacles, and proved "in unmistakable fashion" that he is "a surging national candidate." The "genuine surprise" of the night is that Santorum is now winning close primary races, says Neil Stevens at RedState. In "real, standard elections, he's standing up to the mighty Mitt Romney, and he's winning." This is new for Santorum, and it makes him "a lot more electable than he seemed."

2. Gingrich's bid is all but done
Newt Gingrich just struck out, says Alan Silverleib at CNN. His whole campaign rationale depended on winning "in the heart of Dixie," and second place in both races isn't enough. Gingrich says he's still in this for the long haul, but "bravado aside, at some point the money dries up and voters stop listening." Newt has resurrected his campaign before, "but there won't be another comeback. Not this year," says Matt Lewis at The Daily Caller. And if Gingrich truly believes that Romney is a fake conservative who can't win, "he owes it to Republican voters to give... Santorum a clean shot at wresting the nomination from him. I'm pretty sure Santorum has earned it."

3. Romney is still easily winning the delegate race...
"It may not be pretty, and it lacks cinematic punch, but Mitt Romney's relentless strategy of delegate accumulation is still paying off," says Neil King Jr. in The Wall Street Journal. Indeed, Santorum won the Deep South primaries, but basically tied Romney in the night's total delegate hauls. Team Romney's "'math' spin is sad, but not crazy," says David Weigel at Slate. It's how Barack Obama beat Hillary Clinton in 2008. The real "silver lining for Romney" is Gingrich's vow to stay in the race, says Jennifer Rubin at The Washington Post. The split conservative vote "will help keep Santorum's delegate count low" while Romney keeps or adds to his lead.

4. ...But he's starting to look less "inevitable"
"If you accept a narrow reading of the delegate math," Romney is probably "still the inevitable nominee," says Ed Rogers at The Washington Post. But he still looks weaker with every loss. I'd go so far as to say "it's impossible for Romney to make the case that his nomination is inevitable when he keeps putting 'L's' on the board," says Chris Cillizza at The Washington Post, especially given his "inability to win a single Southern state." Romney will win those states if he's the nominee, says Michael Tomasky at The Daily Beast. But after this Southern vote of no confidence, "Romney is just barely hanging on by the thinnest thread that exists."