(CNN) -- Rick Santorum's clean sweep in Colorado, Minnesota and Missouri on Tuesday was the latest plot twist in what was already a potboiler of a Republican presidential campaign. Here are five things we learned from Tuesday:
Minnesota rejects Romney
Don't believe the spin: Mitt Romney wanted to win Minnesota, and lost.
The Romney campaign sent reporters a "Reality Check" memo on Tuesday morning downplaying the importance of Colorado, Minnesota and Missouri, correctly pointing out that delegates in the states will not be allocated until later this year.
"It is difficult to see what Gov. Romney's opponents can do to change the dynamics of the race in February," wrote Romney political director Rich Beeson. "No delegates will be awarded on February 7 -- Colorado and Minnesota hold caucuses with nonbinding preference polls, and the Missouri primary is purely a beauty contest."
OK, but as recently as a few days ago, Romney's staff was taking Minnesota very seriously.
Remember: Romney flew straight to Minnesota, a state he won in 2008, the morning after his win in the Florida primary last week.
A super PAC supporting the former Massachusetts governor spent money on television ads in Minnesota. The Romney campaign pumped anti-Santorum robocalls into the state.
The Romney team even had tentative plans to send the candidate to Minnesota the day after the Nevada caucuses, but backed away from that schedule when it became clear that Santorum was the Republican candidate resonating with the state's small, conservative caucus electorate.
Despite the best efforts of Romney-world to downplay the importance of Minnesota, the campaign played to win there.
Romney's third-place finish in Minnesota behind Santorum and Ron Paul was a very real loss for the national frontrunner.
Swing state Santorum
Tuesday night's results handed Santorum a compelling talking point as he makes the case that he is better qualified than Gingrich to be the conservative alternative to Romney -- that he can appeal to voters in key battleground states.
Santorum has won four swing states this primary cycle: Iowa, Missouri, Minnesota and Colorado. Romney won three: New Hampshire, Florida and Nevada. Gingrich won South Carolina, which will be firmly in the GOP fold come November.
The former House Speaker's nomination strategy also focuses largely on southern states that will not be competitive in the general election.
After his strong Midwestern showing on Tuesday, Santorum can now plausibly make the case that he can run a national campaign like Romney, rather than a regional one like Gingrich.
Low turnout, again
Are Republicans energized? Not if turnout is an indication.
Early reports show fewer voters participated in Tuesday's primary and caucuses than in 2008.
Missouri had an excuse -- voters knew the primary didn't mean anything more than a popularity contest -- the real vote takes place when the state holds caucuses on March 17 -- so that could explain low numbers.
Robin Carnahan, the Missouri secretary of state, had predicted a 23% turnout. It didn't come close to that.
Tuesday's low numbers follows turnout in Florida last week, which was down 14% from 2008 and Nevada, which was down 26% from the last election.
Some say the turnout reflects an ongoing unhappiness with the Republican field while others say it's the bitterly negative tone of the campaign.
Republicans say it will be different in November when they're running against the president.
The reaction at 1600
In his victory speech, Santorum told supporters that Romney and Obama were hearing their cheers then reconsidered about the president.
"I wouldn't be surprised if he isn't listening. Why do you think he would be listening now?" Santorum asked.
Apparently, someone at the White House was listening — an Obama aide had a different take on the results than Santorum's.
"The Santorum victory in Missouri is a sign the base of the GOP doesn't trust Mitt Romney," the aide said. "Right now, Romney should be locking up the nomination, not losing contests. This weakness will follow him into the general election."
Retail politics, again
Santorum's win in Missouri wasn't really a surprise — Gingrich wasn't on the ballot, Santorum had no one to have to split the conservative vote, and Romney put little into the state.
Minnesota was a surprise. Colorado was a stunner, given Romney's success in the state in 2008.
Romney made several stops in the state, including one on the day of the Nevada caucuses on Saturday. But after bailing on Florida and Nevada, Santorum spent nine days in Colorado around trips to Missouri and Nevada talking to voters and shaking hands.
That's the same strategy credited for his upset win over Romney in Iowa, where be pretty much took up residence in the months leading up to that state's caucuses on January 3.