Businessman Donald Trump, right, and Ben Carson appear during the CNN Republican presidential debate at the Ronald Reagan Presidential Library and Museum in Simi Valley, Calif.(AP Photo/Mark J. Terrill, File)

Two men who have never run for any office before currently comprise the top tier of the 2016 Republican presidential field. As Philip Bump wrote in this space earlier today: "There's [Donald] Trump. There's [Ben] Carson. And then, way, way, way, way back there, there's everyone else."

That's right. And it's a reality that continues to baffle the entire political class -- Republicans, Democrats and, yes, journalists.

The best explanation I've seen of late comes from a focus group run by Peter Hart, a Democratic pollster, on behalf of the Annenberg Center for Public Policy at the University of Pennsylvania. The group, which was in Indianapolis, was comprised of 12 Republicans, 11 of whom are "hardcore" GOPers. (Before you lambast the idea of a Democratic pollster leading a GOP focus group, Hart helped conduct the bipartisan NBC-Wall Street Journal poll for years and is widely recognized by pollsters in both parties as one of the best in the business.)

One comment, from a woman who identified herself as a Trump supporter, really stood out to me. Here it is:

America doesn't want a politician. We're sick of career politicians. We did what we were supposed to do. We wrote the letters, we made the phone calls, and they did not listen, and we're out to clean house.

Totally fascinating. And very insightful. It's not just that people are sick of politicians. (We knew that.) It's that Republican voters feel like they were sold a bill of goods. They were told that if they voted Republicans into majorities in the House and the Senate, things would change. Then they didn't -- or , at least, not as much as they had hoped. There's a sense of betrayal that undergirds the anger. That makes for a toxic brew that wants everyone at every level in both parties out.

Now, it's also true that the belief among rank-and-file Republicans that their elected officials didn't change things like they said they would reflects a fundamental misunderstanding of how much you can get done when your party doesn't control the White House. The idea that Republicans in the House and Senate could, say, repeal the Affordable Care Act with President Obama in the White House is a fantasy. It's simply not possible.

But, that's sort of besides the point as it relates to the average GOP voter. When someone like Trump or Carson emerges promising to stand up for Republican principles in ways that the current leadership in the party hasn't done, it's immensely appealing. And, because this is a campaign and not actual governance, Carson and Trump don't need to engage with the harsh political realities that led to these "failings" by the congressional leadership. They can condemn -- without repercussion.

And, THAT is what the Republican primary voter wants -- and why Trump and Carson have distanced themselves from the rest of the field. Simple, right?