Ten states vote in the Republican presidential primary Tuesday, and a couple interesting things could happen -- like that Ron Paul might actually win something. There are exciting possible outcomes for each candidate except Newt Gingrich, who hinted he might only win his homestate. Our guide to what to watch for on Super Tuesday.

Ron Paul Actually Wins Something

Scenario: Paul thinks he has a shot in the caucuses in Idaho, North Dakota, and Alaska, calling them "fertile political fields" and "our three best chances," Politico's James Hohmann reports. Paul hasn't won a single state so far, and just eight delegates. His goal has been to have enough delegates to influence the nominee at  the convention.

Likelihood: It's hard to say. There hasn't been polling in any of these three states. Romney had a very big and enthusiastic rally in Idaho Falls last week, though Paul did better than usual in neighboring Washington's caucuses Saturday. He came in second.

How long we have to wait to find out if it happened: Sigh, forever! Polls close in Idaho at 9 p.m. and 10 p.m. eastern time. The results in Alaska aren't expected till 2 a.m.

Santorum Loses Almost Everywhere

Scenario: Santorum wins only Oklahoma. Santorum has slumped in polls, The New York Times' Nate Silver writes, noting that big leads in Ohio and Tennessee have disappeared, and he's lost so much support in Georgia he might not get any delegates out of it. He hasn't been able to do as well in caucus states since his big wins in Colorado and Minnesota. "Without a burst of voter enthusiasm in those states, his relatively weak organization could harm him, possibly leaving Ron Paul as the major rival to Mr. Romney in them instead," Silver writes.

Likelihood: Moderate. You can see Santorum's drop in support through Real Clear Politics' nifty graphs. On the other hand, polls have underestimated Santorum's support by an average of almost 5 percentage points, U.S. News' Lauren Fox notes.

How long we have to wait to find out if it happened: Oklahoma polls close at 8 p.m. Alaska results aren't due till 2 a.m.

Romney Passes Another 'Crucial Test' of Winning Evangelical Whites

Scenario: Romney wins Tennessee. All primary long, reporters have been setting up these "tests" for Romney to prove he can get some votes from less-affluent, more-religious voters, who might otherwise be inclined to think he's too rich and too Mormon. Romney keeps passing these tests -- Florida, Nevada, even conservatives in New Hampshire -- and it's never good enough to avoid another crucial test. Ohio was set up to be Romney's this-time-it's-really-for-real test, but before voting started, he pulled even with Santorum in polls. So a new test was created: Tennessee. (Examples: here, here, here, and here.) One in five Tennessee voters think Mormonism is a "cult." And yet Romney's doing okay there.

Likelihood: Somewhat likely. Santorum once had a big lead over Romney, but it's slipped, and the most recent poll, from WeAskAmerica, shows Romney ahead by 1 point.

How long we have to wait to find out if it happened: Polls close in Tennessee at 8 p.m.