If Trump isn’t able to hit the magic number of 1,237 -- the number of delegates needed to become his party's nominee -- the splintered field will set a contested convention into motion.
Here are five steps that Trump can take to secure the nomination in the coming weeks:
1. The Big Three
The March 15 primaries in Florida and Ohio may be do-or-die for Marco Rubio and John Kasich, but they’re also crucial for Trump. These two contests – plus Arizona on March 22 – mark the three largest winner-take-all primaries on the entire election calendar.
Trump would ideally like to win all three of these states – worth a combined 223 delegates, but he can afford to lose one and still be on pace for a photo finish. If he’s able squeak out a win in all three, it will be possible for him to lose a majority of the remaining delegates and still win the nomination.
But pay attention to other big players on March 15: Trump needs to take big delegate hauls especially in Illinois and Missouri, where winning several congressional districts can quickly boost a candidate’s delegate count.
2. Home Field Advantage
Trump needs a strong performance in his home state of New York.
A few of the state’s 95 delegates in the April 26 contest are divided up proportionally based on the statewide vote, but most come from winning in the 27 congressional districts. The winner of each district gets two delegates while second place gets one – that is, unless Trump can top 50 percent to win all districts.
The real estate mogul should aim to score about two-thirds of the state’s delegates, especially if he loses either Florida, Ohio or Arizona.
3. Other States To Watch in April and May
If Trump is able to clear the right hurdles, the next two months will need to be slow and steady. April and May mark a stretch without any major winner-take-all states, but Trump will need to keep ticking upward in the count if he wants to hit 1,237 delegates.
He’ll have two delegate-rich Midwest states in Wisconsin and Indiana, both of which are “winner-takes-most” states, allowing him to make some large strides if he can win across all regions of the state.
He’ll also need to pick up three smaller East Coast states voting on April 26 – Delaware, Maryland and Connecticut – which are either winner-take-most or winner-take-all worth a combined 82 delegates.
4. States Trump Can Afford To Lose
Although Trump’s road to the nomination will require a large number of wins, he can afford to take a few losses, like Nebraska, Montana and South Dakota -- rural, winner-take-all states that are more friendly to Ted Cruz.
Cruz also likely has the edge in the Utah, North Dakota and Wyoming caucuses, which also tend to be more friendly to Cruz. Trump can afford to cede some ground, but needs to accumulate some delegates to minimize the damage.
5. Two Must-Win States On The Final Day
Even if Trump can clear all the hurdles by this point, he’ll have two big ones to clear on June 7, the final day of voting: New Jersey and California.
New Jersey is simple: win the state and you get all 51 delegates.
But virtually all of the 172 delegates at stake in California are divided up based on who wins each congressional district, which means Trump’s bid for the outright nomination may come down to whether he can deliver a broad victory in the Golden State.