Donald Trump has a commanding lead in a new poll of Indiana's primary — and if the Hoosier State's results this coming Tuesday resemble this poll, they'd likely spell doom for Ted Cruz's already-flailing campaign.

The poll, from NBC / The Wall Street Journal / Marist, shows Trump winning 49 percent of the vote, to Cruz's 34 percent and John Kasich's 13 percent.

This margin is an outlier, since most recent polls have shown a closer race. But this is just one of six recent polls showing Trump leading.

Cruz's team surely hopes that these polls are wrong, and that the one recent poll showing the Texas senator ahead (by quite a lot!) is the correct one.

But if a report this weekend by Politico's Alex Isenstadt is any indication, the Cruz camp is seeing similarly grim indicators privately. Before this poll was released, Isenstadt wrote that several Cruz aides anonymously "expressed growing alarm that Cruz would lose Indiana’s primary," and that some in the campaign "are turning to the question of what’s next."

Why a loss in Indiana may put the nail in the coffin for Cruz's campaign

A Trump victory in Indiana would not technically give the billionaire a majority of delegates — he can't clinch that until the final day of voting, on June 7. And it wouldn't mathematically eliminate Cruz from winning on the first ballot, because that's already happened.

Yet Indiana is so important because it was one of just a few remaining states that looked like they could send either a big delegate haul or nothing at all to Trump, thus either greatly helping or somewhat complicating his path to a majority.

After all, Cruz had recently won a solid victory in Wisconsin, and Trump has performed unevenly in the Midwest. Cruz had at least been kinda close in polls. And Indiana allots its delegates winner-take-all, both statewide and by congressional district, so even a narrow defeat for Trump could mean missing out on most of its 57 delegates.

But if those delegates instead go into Trump's column, then considering how the rest of the calendar breaks down, he'll have a relatively easy path toward his majority, rather than a difficult one. He looks very strong in West Virginia and New Jersey, and is assured of some delegates from proportional states of Oregon, Washington, and New Mexico.

If all that happens, Trump will only need to win a relatively small number of Congressional districts in California to put him over the line — and if he wins big in the Golden State, he'll clinch easily.

Furthermore, if Cruz can't win Indiana considering all he seemed to have going for him, there's very little reason to believe he can win California, which is the most important state remaining, and where Cruz is even further behind in recent polls.

Cruz may well try to prolong the campaign for another month even if he loses in Indiana, in hopes of a miracle in California. But with Republican elites seemingly more and more resigned that Trump will be their nominee, and lacking the appetite for a protracted convention battle, he'd likely be simply delaying the inevitable.