After all the hype, media appearances and debates, the official launch to see who will succeed as the Republican and Democratic presidential nominees begins in earnest on Feb. 1, when the first party supporters will cast their votes in the next race to the White House.
"Unlike just about any other election in the democratic world, the nomination process is a sequence of elections," says Elaine Kamarck, author of Primary Politics: Everything You Need to Know about How America Nominates Its Presidential Candidates. "Each contest then builds on the previous contest, which is why Iowa and New Hampshire have such outsized support."
- Race for the White House: 6 things to know about the U.S. primary process
- CBC IN IOWA | Ted Cruz, likable or not, wins over Christian Iowans
- Iowa caucuses going down to the wire as U.S. primary season kicks off
- Clinton, Sanders make Iowa appeal in town forum
The whole process lasts until June, culminating in each party's national convention.
To win the nomination, a candidate must secure 50 per cent of the delegates plus one. The Democrats have not yet finalized their delegate numbers but they are estimated to be 4,764. The Republicans have 2,472, so a candidate must win 1,237 delegates.
As the first state to go, the results in Iowa are of particular importance, setting the tone for the primaries and caucuses to come.
On the Democratic side, we will learn whether Bernie Sanders, the self-proclaimed "democratic socialist," will be able to squeak out a victory over Hillary Clinton, who long ago was thought to have had the race wrapped up.
But the Republican Iowa caucus results may prove much more compelling. With all the hype and strong polling numbers around Donald Trump, Iowa will give us the first clue whether the New York real-estate magnate has been able to convert this support into actual votes.
Iowa, which holds a caucus, is followed by New Hampshire, which holds the first primary. The results can effectively help clear the field, weeding out lesser candidates who may drop out if they receive low support.
To better follow along with what can be a confusing process, here are six things to know about the U.S. primaries.
Difference between a primary and a caucus
The difference between a primary and a caucus is that the state itself conducts a primary, while the state party runs a caucus. A primary takes the form of a traditional election, with a broad group of voters casting secret ballots at polling stations that are open all day. This also means primaries are government-funded, making them the preferred choice for many states.
But caucuses — typically held in churches, school gymnasiums, libraries, community centres and, increasingly rare, at people's homes — meet to openly discuss the candidates before voting. Caucuses also use the meetings to conduct other party business, such as selecting delegates.
Difference between an open and closed primary
Most primaries are closed, meaning registered Republicans must vote in the Republican primary and Democrats in the Democratic primaries.
But in some states, regardless of one's political affiliation, a registered voter can choose to vote in either primary. But not both. So why would a true blue Democrat, for example, want to vote in the Republican primary? It may be a strategic vote.
Joshua Putnam, a political science professor at the University of Georgia, said there was some anecdotal evidence in the 2012 Michigan primary that with Barack Obama running unopposed, some Democrats instead voted for Rick Santorum in the Republican primary, thinking he would be a weaker candidate for the president to face off against.
What is Super Tuesday?
Super Tuesday is the day on which the largest number of states hold their primaries and caucuses. This year, Super Tuesday falls on March 1, with 14 states and America Samoa taking part.
"The dynamics of the race change on Super Tuesday. Instead of looking at who won a state and who came in second or third, it will be the first time that a large number of delegates are selected to the convention," Kamarck said.
"And so what will matter coming out of Super Tuesday is not just who won which state, but how many delegates they picked up on that day."
In 2008, Hillary Clinton did very well on Super Tuesday in some big states. But Kamarck notes that Barack Obama came out with a delegate count almost equal to hers in the end.
- Neil Macdonald: Can America's political discourse get any cruder?
- Will Donald Trump's Iowa debate boycott help or hurt him?
"Super Tuesday can be the beginning of a long, contested race that goes to June, or it could be the end, particularly if one candidate sweeps it up," Kamarck said.
How delegates are awarded
Delegates are usually active members of the party or party supporters who have been chosen to represent their state at the national convention. They then cast the votes that will determine the final presidential nominee.
Since how these delegates vote is decided during the primaries and caucuses, much of the national convention is somewhat of a roll call, with all of the states pledging their support behind a candidate.
The number of delegates each state gets is determined at the national party level. Both parties have a different formula for arriving at this number but it's primarily based on population. California has more delegates than a state like Wyoming.
But the process also builds in a party loyalty bonus, meaning if your state is traditionally more Republican, it will get an extra allotment of delegates, Putnam said.
How delegates are allocated
Again, the Republicans and Democrats have different rules.
The Democratic National Committee requires proportional allocation from all its states: basically if a candidate gets 40 per cent of the vote in a state's primary or caucus, then they get 40 per cent of that state's delegates at the national convention. But a candidate must receive a 15-per-cent qualifying threshold to receive any delegates.
With the Republicans, it gets a little more complicated, as each state has different rules. The first four states to go — Iowa, New Hampshire, South Carolina and Nevada — are not bound by rules of allocation and can choose any method of allocation. These methods include proportional, winner takes all or a hybrid. However, in the first two weeks in March, the 14 states that hold that their contests on Super Tuesday, along with four other states, have to be "proportional."
But as Putnam points out it doesn't necessarily work out that way.
"It doesn't work out in a way [that] if you win 40 per cent of the vote, you get 40 per cent of the delegates," he said. "It's more complicated, it varies from state to state. Some states don't have a threshold for qualifying for delegates, others allow for a threshold of 20 per cent of the vote to qualify for any delegates."
After March 14, for the Republicans, states can choose whatever delegate allocation method they want.
Bounded, pledged and 'superdelegates'
Most Republican delegates are bounded, meaning if they have been allocated to a particular candidate, they must support that candidate at the national convention. However, each state is awarded so-called "RNC delegates," unbounded delegates who are party officials with automatic credentials to the convention. This presumably gives an establishment candidate a leg up, according to RealClearPolitics.
On the Democrat side, there are pledged and unpledged delegates, Putnam said. However, unlike the Republican process, the candidates have the final say over the delegates who are pledged to them.
"That right of refusal means that the delegates end up being quite loyal to the candidate to whom they are pledged," he said.
Superdelegates, however, are unpledged delegates, meaning that they can throw their support behind whomever they choose.
But the bulk of the superdelegates are found in the Democratic party, with more than 700 selected for 2016. These superdelegates are party brass and elected officials, such as senators, members of congress and governors.
In the 2008 primaries, Hillary Clinton led the superdelegate count over Barack Obama, prompting speculation that the close race could come down to these unbounded votes, regardless of Obama's victory in the primaries and caucuses. In the end, Obama had secured enough superdelegate support, and Clinton conceded defeat.