Donald Trump is many things, but a deep thinker with a nuanced grasp of the complexities of public policy is not one of them. Yet he stands firmly at the front of the GOP presidential pack largely because of one issue: immigration. And before you dismiss his thoughts on the subject as the rantings of a simple-minded xenophobe, understand that more than any other candidate, he's offering Republican primary voters some actual concrete ideas for how to address this challenge.

That isn't to say that those ideas aren't insane and impractical, because they most certainly are. Trump wants to build a wall over all 1,933 miles of the U.S. border with Mexico, which would of course be the most luxurious, super-classy border wall this side of Monte Carlo (is there enough cubic zirconia in the world?). He also wants to round up and deport the 11 million unauthorized immigrants currently residing in the United States.

Say what you will about that, it's an idea. And that's what Republican voters seem to be responding to. Trump offers something emphatic and understandable, where the other candidates hem and haw and hedge.

Yes, building a 1,933-mile-long wall, through rugged terrain and over land held by lots of private owners, would be absurdly impractical and expensive. And arresting and deporting 11 million people would be a staggering task; the cost estimates range from $200 billion to $600 billion.

Even apart from the cost, how could you find all those people without turning America into a police state? But not to worry, because Trump can do it. "Politicians aren't going to find them because they have no clue. We will find them, we will get them out," he told CNN. "It's feasible if you know how to manage. Politicians don't know how to manage." Then after all 11 million are gone, Trump would let some back in "if they're really good people."

Those are the kinds of answers Trump gives to these questions, and should anyone be surprised at their appeal? After all, Republican voters have been told for decades that the answers are always simple and easy, and that if you trust your gut and show strength you can accomplish anything, whether it's turning around the economy or invading and controlling a Middle Eastern country or two.

And on immigration specifically, they seem to agree with Trump, or at least many of them do. One recent poll showed 65 percent of Republican voters saying they had confidence in Trump to handle the issue. Since he got in the race talking about how Mexican immigrants are racists and drug dealers, he's gone nowhere but up.

What are the other candidates saying? For some time now, Republicans have said some version of the following on the issue: "First, we have to secure the border. Then after the border is secure, we can talk about some kind of path to legalization for the people who are here now." What they almost never do is give any detail on what it means to "secure the border." That may be a way to avoid dealing with the undocumented forever, since you can always say that the border isn't quite secure just yet. Or it may be that they really have no idea what we should do that we're not already doing.

Keep in mind that in recent years, the border has become much more secure by any standard. In the last decade, the Border Patrol's funding has doubled, and the number of border agents has increased by almost as much. As The Washington Post reported a couple of months ago, "As the Department of Homeland Security continues to pour money into border security, evidence is emerging that illegal immigration flows have fallen to their lowest level in at least two decades." Net migration from Mexico has fallen to zero, meaning there are as many people moving to Mexico from the United States as vice-versa.

Given those facts, it's a little hard to see what the candidates can say they want to do, other than: "The same thing as Barack Obama, but, you know, more." Which may be why they only talk in vague generalities.

Except for Trump, that is. Trump's border wall and mass deportations are never going to happen, but every primary voter knows where he stands and what he wants to do. In a primary with 17 candidates, 16 of whom are politicians basically pretending that they have concrete and feasible plans to reform immigration policy, that may be more than enough.