Here's a radical thought: What if the latest Iowa caucus polls are basically correct? As we head into voting, there is no evidence that any candidate is collapsing, no evidence that any candidate is zooming upward, and there doesn't appear to be a lot of movement in the top three of Donald Trump, Ted Cruz, and Marco Rubio.

But the ground game — what about that? Yes, it matters, and when it comes to turning out voters, the Cruz campaign appears to have a clear advantage. Team Cruz has built the biggest, most conventional ground operation in Iowa, and it will likely work. So it is reasonable to expect that Cruz will get his 23 percent of Republican caucus voters (the number is from the latest Des Moines Register poll) to the caucuses tonight.

Marco Rubio built his Iowa operation later than Cruz, and it is smaller. In recent weeks, Rubio has followed Mitt Romney's 2012 playbook in Iowa — a playbook that took Romney to a virtual tie for first place. Back then, Romney performed almost exactly as polled. (The final 2012 Des Moines Register survey had him at 24 percent, and he finished with 24.5 percent.) So it would be reasonable to expect that Rubio will get his 15 percent of the electorate out to the caucuses to vote for him.

That leaves Trump as the big question. The Trump organization has said it has a solid ground game, but frankly no one has seen it. On the other hand, reporters and other observers have been looking, without result, for signs of a conventional Cruz-style ground game. More than any other candidate, Trump will rely on enthusiasm and word-of-mouth contacts between his supporters to get them to the caucuses. That is more risky than an operation in which a candidate has thousands of volunteers with the mission of prodding fellow Iowans to vote.

So if there is anyone with a chance of underperforming his 28 percent of the electorate (again, the new Register number), it is Trump. And if Trump does underperform, the question will be whether he falls enough for Cruz to catch him.

One more note about Trump and the ground game. Trump's top Iowa operative is a veteran of caucus politics named Chuck Laudner. He is known and respected by many people involved in politics and in covering politics in Iowa. (That includes me.) He has been extraordinarily close-mouthed about what the Trump campaign is doing to drive turnout. But there is no one who knows Laudner who believes he is doing nothing on turnout. Laudner realizes that Trump's is an unconventional campaign, and he is thought to have fashioned an unconventional turnout operation as well. In a conversation Monday morning, a veteran Iowa politico -- someone who knows Laudner well -- asked, "How can there be a turnout operation and no evidence of it?" but at the same time compared Trump to a general with an army concealed behind a hill. "All we know is that he'll come from where we don't expect," the politico said. Right now, that is the biggest mystery of the campaign.

As far as everybody else is concerned, there is no evidence that any of the single-digit candidates will zoom out of the pack. The pack will stay the pack, until one or more of them decides to quit the race.

There has been an enormous amount of strategic, and perhaps wishful, punditry, in this Iowa campaign. This candidate will collapse. This candidate will surge. Just look at the crowds — the size, the enthusiasm! But remember that the polls have been pretty reliable in the past. And if there is some big discrepancy between the final poll and the vote — such as with Rick Santorum in 2012 — there should be, by now, some evidence that something is happening. (There was, with Santorum in 2012.)

But right now, this looks like an Iowa caucus that could go pretty much as predicted.