The first Republican presidential primary kicked off early Tuesday in New Hampshire, with polls showing Mitt Romney's commanding lead shrinking a bit heading into the vote, thanks in part to rivals savaging Mitt's business record. One tracking poll shows that Romney's support had dropped from 43 percent to 33 percent in the week before the "crucial" vote. But Ron Paul (20 percent), Jon Huntsman (13 percent), and Newt Gingrich (11 percent) were still well behind, and almost all political gurus predict a big win for Mitt. Still, anything could happen. Here, five key questions that will be answered soon after the polls close at 8 p.m.:

1. How big will Romney's win be?
Romney is sitting pretty in New Hampshire, says Michael D. Shear in The New York Times. He has a summer house there, and he was governor in neighboring Massachusetts. This is his home turf. His fundraising edge has allowed him to "blanket the airwaves with positive ads" paired with an anti-Obama message that "sells well in New Hampshire." Of course, Romney's advantages have a downside — they inflate expectations. "If he doesn't win New Hampshire by a significant margin, donors and rivals are sure to question the depth of his support as he tries to move forward." Many insiders believe Mitt needs to hit 38 percent to keep everyone impressed, says Maggie Haberman at Politico. That was John McCain's approximate tally when he won New Hampshire in 2008. But regardless of Mitt's exact percentage, for "a serious bounce, he needs a convincing double-digit win."

2. Who will take second place?
Romney has slipped a bit, but he's still "likely to cruise to victory in New Hampshire," says Scott Conroy at CBS News. The potential for a "blowout" has eroded interest in the state's storied contest. But there's still a crucial race to watch on Tuesday — "the struggle for second place." Even if Romney meets expectations, "how Ron Paul, Rick Santorum, Newt Gingrich and Jon Huntsman fill in the second- to fifth-place slots in New Hampshire will largely determine who has momentum going into the first-in-the-South primary that has been won by every eventual Republican nominee since Ronald Reagan."

3. Will Huntsman pick up speed?
Former Utah Gov. Jon Huntsman "skipped Iowa's caucuses to stake his candidacy on a strong showing" in New Hampshire, says Holly Ramer for the Associated Press. Huntsman has not had much luck winning over wary conservatives, but his appeal to independents, who can vote in the GOP contest, has helped him gain ground, with Huntsman's support climbing several percentage points in the week before the primary. Huntsman is telling supporters he'll defy expectations, and that they'll wake up to "a different political reality" on Wednesday. Can he deliver?

4. Will Santorum fall into the "Huckabee trap"?
Like Iowa caucus winner Mike Huckabee in 2008, Rick Santorum has campaigned hard in New Hampshire, hoping to build on his Iowa momentum. But the former Pennsylvania senator may have "fallen into the same trap that ensnared" Huckabee, says Dan Balz at The Washington Post. Huckabee placed a distant third in New Hampshire — winning just 11 percent of the vote — after squandering time he could have devoted to the next contest, South Carolina, which he only narrowly lost. Santorum's socially conservative views haven't gone over too well in independent-minded New Hampshire. South Carolina, heavy in conservative Christian voters who might like Santorum's message, "looms as a more crucial test for his candidacy." If Santorum finishes fourth or fifth in New Hampshire, he might regret the "precious days" that would have been better spent in the Palmetto State.

5. Will the polls get it right this time?
If you go by the polls, Romney's second straight victory is in the bag. But "pre-primary New Hampshire polling is notoriously off the mark," says Haberman. In 2008, New Hampshire was supposed to be "a second, major win for then-Sen. Barack Obama over Sen. Hillary Rodham Clinton," says Jon Cohen in The Washington Post. "Instead, Clinton won by about two percentage points, setting off the polling industry's biggest reevaluation since the infamous 'Dewey defeats Truman' headlines of 1948." Romney's lead is bigger than Obama's New Hampshire polling advantage in 2008, so "the errors would have to be that much greater to spoil most prognostications about the No. 1 spot." Another 2008-like "fiasco" seems close to impossible this time around — but never discount the possibility of a "big shock" when the votes are counted.