Former Massachusetts governor Mitt Romney’s 8-vote victory over former Pennsylvania senator Rick Santorum in the 2012 Iowa caucuses is only a few hours old — and already is one of the legendary results in the history of presidential politics.

View Photo Gallery: The Iowa caucuses came down to the wire, with Mitt Romney claiming an eight-vote victory. Rick Santorum and Ron Paul won 24.5 percent and 21.4 percent of the votes, respectively.

The main lesson of the night was that every vote does indeed count and that the makers of “Swing Vote” — that horrific Kevin Costner movie — were smarter than we all gave them credit for.

But there were any number of other lessons that we learned (or re-learned) from the results in Iowa on Tuesday. Our lessons learned are below. What did you learn?

* A tie goes to the underdog: Romney won Iowa, a prospect that was unthinkable as recently as six weeks ago. And yet, Santorum is the story today. The closeness of the result — an eight-vote difference is, for all intents and purposes, a pure tie — means that the underdog candidate winds up winning by virtue of the media attention he receives in the immediate aftermath of the vote. Santorum, to his credit, grasped that reality early Tuesday morning — delivering what amounted to a “here’s who I am and here’s what I believe” victory speech to the scads of people outside of Iowa who had never heard of him before.

* Romney is still the favorite: Yes, the story today is Santorum. And, yes, Texas Gov. Rick Perry’s expected departure from the race makes the former Pennsylvania senator more formidable in the Jan. 21 South Carolina primary. But, Romney is still the only candidate with the financial and organizational prowess to run real campaigns in New Hampshire, South Carolina and Florida simultaneously. Also, he won Iowa. (Did we mention that?)

* Negative ads work but....: The decline and fall of former House Speaker Newt Gingrich in Iowa — he finished a distant fourth — can be directly attributed to the avalanche of negative ads that Restore Our Future, a super PAC aligned with Romney, dropped on him over the final three weeks of the campaign. But, if Gingrich’s concession speech last night is any indication, he is out for revenge against Romney for those ads in the states to come. And an angry Newton Leroy Gingrich with nothing (or at least not much) to lose could be a very dangerous thing for Romney.

* Late entrants don’t work: Perry adds his name to an ignominious list of late entrant flame-outs that includes retired Gen. Wesley Clark (2004) and former Tennessee senator Fred Thompson (2008). The lesson: This is harder than it looks, people. Perry entered the race on Aug. 13 as the clear alternative to Romney and by Labor Day was the frontrunner. But his faltering debate performances — and describing his debate performances as “faltering” is like saying Michael Jordan is “pretty good” at basketball — capsized his campaign. Successful presidential campaigns take years of planning to be executed properly. (See Clinton, Bill). Getting in late just doesn’t work.

* Frontrunners get tested: We, as a people, tend to like competition. Because of that tendency, there is almost never a presidential primary race where the frontrunner doesn’t face a serious challenge to his/her dominance. In 2000, George W. Bush was the strongest frontrunner in modern memory and still had to fight off a very real challenge from Arizona Sen. John McCain to claim the prize. Santorum’s tie-goes-to-the-underdog victory last night almost certainly means that a fight Romney has been avoiding with the social conservative wing of the party is coming. And he’ll need to find a way to win it in order to wind up as the GOP nominee.

* Ron Paul is like “Friday Night Lights”: We wrote a while back that the Texas Republican Congressman’s appeal was similar to that of NBC’s now-ended drama about football (and life). Both had/have ardent fan bases that would do anything for them but that fan base simply isn’t big enough to make them popular with mainstream America. In the early going last night, it looked like Paul might pull off the upset. But as votes streamed in, it became clear his ceiling was simply lower than his rivals. Paul wound up with 26, 219 votes — more than double the 11,817 he received in 2008 — but it still wasn’t enough to keep pace with Romney and Santorum. Paul will remain a factor in the states to come because he has such a committed base but he looks like a third wheel rather than a prime contender at this point.

* Organization still matters: The rise of Gingrich in Iowa led us to speculate whether traditional political organizations were overrated in the Internet age. (It’s not a dumptruck, it’s a series of tubes.) But, the top three finishers on Tuesday in Iowa were the three candidates with the best traditional political organizations in the state, apparatus (apparati?) that helped identify and turnout voters when TV ads (Perry) and momentum (Gingrich) didn’t.

* Republicans are divided: If ever you needed a real-life example of the split between the establishment and tea party/social conservative wing of the Republican party, you got it last night. Santorum and Romney were appealing to totally different constituencies within their own party, constituencies that simply see the world through different lenses. Expect Democrats to make much of that fissure today — and in the runup to next November’s general election.

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