It says something profound about Trump's victory that a win that’s been brewing since last July -- when the first-time candidate captured a lead in national polls -- still feels surreal 10 months later, when he finally consummated it.

The billionaire on Tuesday effectively secured the Republican presidential nomination by attrition when his nearest but fading rival, Texas Sen. Ted Cruz, suspended his bid after a distant second-place finish in Indiana. Cruz acknowledged in his concession speech that his path forward "had been foreclosed," and party leaders begrudgingly signaled that the race is, for all practical purposes, over.

Trump himself looked a bit like the dog that caught the car when he stepped up to his podium in the lobby of Trump Tower, the spot where he launched his bid to much establishment incredulity last summer, and tried to make sense of what just happened. "It's been some unbelievable day and evening and year," he said. "And I never have been through anything like this, but it's been a beautiful thing to watch and a beautiful thing to behold."

Despite the call from GOP chief Reince Priebus for swift unity, party regulars -- Washington apparatchiks, donors, and elected officials facing tough fights in November -- will follow their own course in deciding whether to rally around a figure many detest or view as a major liability to the Republican brand. That process will play out in the weeks ahead. And it will likely carry into the party's late July convention, where Trump's refuseniks will have plenty of opportunity to make trouble for their standard-bearer, including over the party platform.

Trump detractors can't exactly mitigate the candidate's worst instincts for hurling divisive invective and tabloid smears. For example, the inclination that led Trump on Tuesday morning to go on national television and promote the ridiculous lie that Cruz's father was somehow complicit in the assassination of John F. Kennedy won't likely change now that he's sewn up the nod.

But the anti-Trump forces in the party can still use platform debate at the convention to confront his bolder challenges to long-held Republican orthodoxy on a range of free-market bedrocks, namely free trade. And with a number of the most prominent Republican names likely to skip out on Cleveland altogether -- including both of the last two nominees -- the Trump camp will have its work cut out to produce an event conjuring the notion of a wholesale rally behind his rise.