A nursery school song ran through my head throughout the first Republican presidential primary debate in August.

It was, "One of these things is not like the others . . . ," a catchy little number from early Sesame Street episodes. (Warning: Listen to it online and it'll stay with you all day.)

But I didn't hear that tune on Wednesday when Republicans debated in Colorado. Not even a bar note.

More coverageOpinion and analysis about the 2016 presidential campaign

For the first time, Donald Trump looked pretty much like everyone else on stage -- like a candidate for public office, albeit a somewhat inexperienced one.

I thought this might happen, even predicted it, but I always feel a happy twinge of surprise when I'm right. Trump is being molded into a semi-conventional candidate by his handlers right before our eyes, and by the pride-crushing demands of the campaign trail. It's turning him into what he was supposed to abhor -- a politician.

I've seen this before. But on a smaller scale. A businessman or other professional gets tired of watching the clowns and decides to jump into a political race to show them how it's done. Within a few months, he sounds just like everyone else, although usually not as good.

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Politics can be humbling, and getting elected to public office is a lot harder than it looks. Those clowns work unimaginable hours. Eighteen-hour days are the norm, seven days a week. Every minute in a good campaign is accounted for: If you're not meeting voters, you're dialing for dollars or doing radio hits or getting briefed for the next campaign stop. And everywhere you go -- every rally, ever diner stop, every door step -- you have to be on your "A" game, mentally and emotionally. Tired is no excuse. Make one mistake in a media interview and it can take your campaign weeks to get back on message, if ever.

There's a reason politicians sound the way they do.

So there stood Trump on Wednesday, not alongside the pack, but as part of the pack now. And for the first time, I swear, I could see a grudging respect from The Donald toward the other candidates, and perhaps, even, from the other candidates toward Trump. After all, he's in the show now, too.

But can a tethered Trump can keep his base of disaffected voters and attract converts? Or will he soon start looking to the outraged like just another say-anything politician?

That's always been the intrinsic question about a Trump candidacy. It shouldn't take long to find out now.

William F. B. O'Reilly is a Republican consultant.