Why Indiana Could Make or Break Trump's Path to the Nomination

The 57 delegates at stake in Indiana next Tuesday could be a tipping point.

— -- Republican presidential front-runner Donald Trump has made some major delegate strides in across the Northeast over the last two weeks. But what does he need to do from here to hit the magic number of 1,237 delegates on the first ballot at the convention this summer?

His path to the nomination may come down to Indiana next Tuesday, according to an ABC News analysis of the delegate count and future allocation rules.

If Trump wants to become the presumptive nominee by hitting 1,237 bound delegates before Cleveland, he will almost certainly need to win Indiana. If he loses Indiana, he still has a viable path to 1,237 delegates on the first ballot with a broad win in California plus unbound delegates.

Here's why Indiana could tip the scales for Trump in the fight for the GOP bid:

Why Is Indiana So Important Next Tuesday?

Indiana is a winner-takes-most state worth 57 delegates. The winner of the state will likely win at least 45 delegates -- more if he wins in most regions of the state. The losers will likely be kept in the single digits, depending on whether they can win any congressional districts. This 40-delegate swing between winning and losing in Indiana could prove crucial to whether Trump reaches 1,237.

What Happens If Donald Trump Wins Indiana?

He would have a likely path to winning the nomination on the first ballot -- and the possibility of clinching the nomination with bound delegates in early June. He will need only 44 percent of remaining delegates to win.

And What If Trump Loses Indiana?

A clear path would still exist for Trump to win on the first ballot using unbound delegates, but his path to clinching on June 7 gets narrower. He will need 53 percent of remaining delegates to win.

If He Wins Indiana, What’s His Path to 1,237 Delegates?

A Trump win in Indiana means less pressure to win big in California. If Trump wins Indiana, he will likely hit 1,237 on the first ballot at the convention even by winning just half of California’s congressional districts.

May 10: West Virginia -- Delegates are elected directly on the ballot via a complex process. Trump should win roughly 20 of the 34 delegates here to keep pace.

Nebraska -- Trump can afford to lose this winner-takes-all state to Ted Cruz.

May 17 and 24:

Oregon and Washington -- Trump should win his share of proportional delegates.

June 7:

California -- This state’s 172 delegates are doled out mostly to the winners of each congressional district -- three for each CD won. The overall winner gets 10 additional delegates. A win in Indiana would allow Trump to have a lackluster showing in California, even losing the state overall as long as he carries about half of the congressional districts.

New Jersey -- Trump needs to win this winner-take-all state worth 51 delegates.

South Dakota and Montana -- Trump can afford to lose these winner-takes-all states to Ted Cruz.

New Mexico -- Trump wins his share of proportional delegates.

This path allows Trump to lose lots of unbound delegates:

All 13 remaining uncommitted unbound delegates in Pennsylvania. He's already won 39 of them, according to ABC News reporting.

All 57 remaining uncommitted unbound delegates from other states like North Dakota, Louisiana, Colorado, Wyoming, West Virginia and Oklahoma.

Can Trump Clinch With Bound Delegates Before the Convention If He Wins Indiana?

Yes. He will need to win about two-thirds of the congressional districts in California or surprise in a Cruz-friendly winner-take-all state if he wants to clinch the nomination with bound delegates on June 7.

If Trump Loses Indiana, How Will He Make Those Delegates Up?

If Trump wants to clinch the magic number in bound delegates only by June 7, Trump will need to win almost every congressional district in California or pull off a surprise win in a Cruz-friendly winner-take-all state –- an unlikely path.

An easier path awaits for him to hit 1,237 on the first ballot of the convention. Winning roughly two-thirds of the congressional districts in California would likely boost him to the magic number, because unbound delegates he’s already won in Pennsylvania, as well as other unbound delegates from other states, are included in this count.