Or it will be Donald Trump.
Those, remarkably, are the only options. In a sense, we're going to make history no matter what, either by electing the first member of a new social group or by electing a guy who ran against every single rule of electoral politics.
This wasn't pre-ordained. Cruz was the first candidate in the race, so there's always been someone other than a white male running (conflating "white" with "non-Hispanic white" for the sake of ease). As more and more people started entering the race, the balance tipped toward the white-male end of the spectrum. But since there were so many white males running and since so many of them didn't do that well, we're left with seven candidates, four of whom are Hispanic, black or female and one who is Jewish.
In the year of Trump, it's easy to forget how much support there's been in the Republican Party for this diverse slate of candidates. With the ascent of Ben Carson, Carly Fiorina and Cruz last year, more Republicans backed non-white male candidates than white male ones. It's gone up and down a bit since, with a quick back-and-forth as Marco Rubio surged after Iowa and John Kasich surged after New Hampshire.
But overall, the party is about split.
Most of those Republicans, we assume, would be quick to point out that their choice of candidate has nothing to do with race, ethnicity or gender. Fair enough. But that doesn't detract from how historic the election is shaping up to be. (Barring, of course, a candidate ex machina running as an independent or chosen at the convention.)
Only one man, it seems, stands between now and the inauguration of the first woman or first Hispanic chief executive. That man, consistent with his brand, is Donald Trump.