Super Tuesday is here, and as the presidential race goes national, Hillary Clinton and Donald Trump are hoping to put themselves way ahead. Ted Cruz and Marco Rubio need strong turnouts to show they can fight Trump over the long-term. And Bernie Sanders hopes to stem Clinton's momentum with a few wins of his own.
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Voters of both parties in Alabama, Arkansas, Georgia, Massachusetts, Minnesota, Oklahoma, Tennessee, Texas, Vermont and Virginia go the polls or caucus Tuesday. Democrats also caucus in Colorado and Republicans will do the same in Alaska.
Here's what to watch on the biggest day yet in the 2016 race:
How completely will Trump dominate?
Trump is cruising nationally -- with 49% support compared to Rubio's 16% and Cruz's 15% in a new CNN/ORC poll, giving him his largest lead yet.
He's likely to blow out the competition in Massachusetts, Tennessee and Alabama, polls there show.
But it's also possible Trump could win all 11 states -- or come close to it. And if he does, it would leave other Republicans with very little hope of catching up.
Cruz and Rubio have spent recent days leveling a dizzying array of charges against Trump. Cruz has raised his decades-old ties to mafia bosses who controlled New York's construction industry and prodded Trump to reveal what he told The New York Times in an off-the-record conversation about immigration. Rubio has hammered Trump as a "con artist," pointing to his hiring of undocumented immigrants on construction projects and his namesake university. And Trump ran into trouble when he failed to disavow the KKK and white supremacist David Duke to CNN's Jake Tapper.
If Trump runs the table on Super Tuesday, or comes close, it'll be yet more proof that attacks and insults -- true or not; subtle or direct -- only make him stronger.
It'll also leave him with a massive delegate lead and a weakened crop of competitors.
The biggest day of Ted Cruz's political career
He hasn't been shy about it: Ted Cruz says Super Tuesday is "the most important day in the entire election."
After days of relentlessly building expectations, the pressure is now on the Texas senator to perform.
The first big question: Does he win Texas -- and by a big margin? If Cruz loses his home state, it will be both embarrassing and mean he's in for a very though night nationwide, leaving him with no path forward in the campaign.
The second big question: Does he win anywhere else?
Cruz's strategy of racking up Southern and evangelical votes has been wrecked by Trump. Now, Cruz is trying to win delegates wherever he can. Four states could represent Cruz's best hopes: Oklahoma and Arkansas, his two neighboring states; Alaska, with its libertarian streak; and Georgia, a delegate-rich state that all three leading contenders see as in play.
He's also looking over his shoulder at Rubio. If Cruz wins Texas and at least one more state, and Rubio doesn't notch any Super Tuesday victories at all, it would put the Texas senator in much better position to argue that he is the true Trump alternative in the field.
Can Rubio win?
Rubio captured second place over Cruz in South Carolina. Then he consolidated the GOP establishment's support after elbowing Jeb Bush out of the race. Then he unleashed the most vicious attack on Trump of any candidate yet, in person, on the debate stage last Thursday and continued his barrage of insults over the weekend --- including some Trump-level personal zingers.
Now, he needs wins.
For all the hype his campaign has received in recent days, Rubio has gone 0-for-4 in the early states -- and unlike Cruz, whose home state votes, there are no locks on Tuesday's map.
Rubio's best bet is probably Virginia, where the GOP establishment makes up much of the northern portion of the state.
He also hopes to compete in Georgia, where he could win in the Atlanta suburbs. Rubio campaigned there Monday alongside South Carolina Gov. Nikki Haley, a particularly effective surrogate.
But a nightmare scenario for the Florida senator and his backers is an 0-for-11 night, coupled with Cruz notching more than one victory. That would continue the race's status quo -- with Trump as the commanding front-runner and the rest of the party's electorate split between the two freshman senators.
Rubio won't be leaving the race anytime soon, no matter what happens Tuesday. He's got money, establishment backing and his home state of Florida votes on March 15.
But his path is increasingly narrow. Ohio Gov. John Kasich remaining in the race complicates not just the Buckeye State -- another winner-take-all March 15 primary -- but other Great Lakes states like Michigan and Illinois, where Rubio also needs strong showings.
Can Clinton put it on ice?
The lay of the Democratic land is pretty clear.
Clinton, coming off a massive 48-point South Carolina blowout win, is likely to parlay her strength among minority voters into wins in Texas, Georgia, Virginia, Tennessee, Alabama and Arkansas.
Sanders, meanwhile, is targeting states that are whiter and, mostly, farther north: Colorado, Massachusetts, Minnesota, Oklahoma and his home state of Vermont. But only Vermont is a guaranteed win for him. If Clinton can carry her success in South Carolina across the rest of the South and pick off a couple of Sanders' targets, he'd be hard-pressed to catch her.
And even if he locks them in, Clinton's stronger states outnumber his, nearly two to one, in the delegate count.
Barring disaster, Clinton's delegate lead is certain to grow Tuesday. And given her long list of superdelegate endorsements, she could make it tough for Sanders to ever catch up.
The real date Clinton and her supporters have circled on the calendar is March 15. It's when Florida, Ohio, Illinois, North Carolina and Missouri all vote -- and when Clinton's backers hope they can land the knockout blow.
She's already looking forward to the general election, taking on Trump in speeches while de-emphasizing attacks against Sanders.
Sanders' latest minority test
Sanders is set to raise $40 million in February, according to the campaign, so he will be competitive for the foreseeable future. The problem is he needs to find new voters.
His New Hampshire win and close call in Iowa came on the backs of white voters. But faced with a more diverse electorate in the past two races, he has faltered. Minority voters in Las Vegas helped Clinton win the caucuses there and the primary in South Carolina.
Sanders has worked for months to reach out to minority voters -- particularly, in recent days, by portraying Republican attacks on President Barack Obama as racially motivated. But to keep the delegate count close, he'll have to succeed Tuesday where he failed just Saturday.
It's an increasingly important challenge for Sanders. After Tuesday, the next major states to vote are Michigan, followed by five on March 15, all with significant minority populations.
There are four key states to watch for Sanders on Tuesday. Wins in Colorado and Oklahoma could bode well for Sanders' ability to rack up delegates in more rural western states throughout the latter half of March and early April. A win in Minnesota is a good sign as Great Lakes states begin to vote. And a win in Massachusetts would underscore the strength of his support among liberals -- the types of people he hopes will eventually help him win California, and therefore, the nomination, on June 7.
But that's a very rosy scenario that doesn't look likely right now.