It's been a long road to the Republican nomination since I was last here in Cleveland moderating the very first Republican debate in August 2015 for Fox News. Back then, the top 10 candidates stretched [1] across two stages, but the man who everyone said would fizzle after some withering questions and a series of candidacy-crippling comments (see: John McCain is not a hero [2] and deporting all undocumented immigrants) has emerged victorious — Donald Trump [3].

It will be an unconventional convention to be sure. At one point, campaign manager Paul Manafort promised Cleveland would be "the ultimate reality show." [4] No past presidents will be attending, and even the other GOP contenders are largely taking a pass. The GOP powers-that-be have felt an earthquake rumbling beneath them, and they have either jumped ship to stay home and lick their wounds or they've thrown in their lot with the winner and crossed their fingers in hopes that he's actually onto something in the nerve he's touched in America.

Fox's America's Newsroom co-anchors Bill Hemmer and Martha MacCallum moderate the Republican debate in Iowa in August 2015.

Even now, before the convention has started, Trump is proving it will be quite unpredictable. Take the botched roll out of his VP announcement of Indiana Governor Mike Pence [5] last week. The horrific killings in Nice [6] and the leaks that it was Pence somewhat undercut the big moment, so Trump took to Twitter to make the announcement — another first — forced perhaps by a looming deadline for Pence to either register to run as Governor of Indiana again or pass to take on the VP race.

The real estate mogul/reality TV star is about to step on that big stage Thursday and become the GOP nominee, and as he has said, the campaign will start in earnest in Cleveland. He'll need the momentum as he goes up against one of the toughest bare knuckle politicians in modern history. Hillary Clinton has now finally made it to the race of her life, and she will not give up the moment without a brutal political cage match.

So here you are America — two candidates with the highest unfavorable ratings we've seen are going to slug it out, and it all begins in Cleveland. Stay tuned!

Martha MacCallum co-anchors Fox News Channel's America's Newsroom [7] on weekdays at 9 a.m.