Republican Herman Cain boasted the other day that he’s a “top-tier” presidential candidate, and the rest of the GOP field is afraid “that this long shot may not be a long shot any longer.”

At a certain level, I suppose there’s some truth to this. Though the Republican top tier has fluctuated quite a bit over the last several months — including, at various times, Romney, Perry, Pawlenty, and Bachmann — Cain can credibly claim a slot, at least for now. Recent polling shows him at or near the top of the multi-candidate field, even surging to the lead in some states.

And yet, when the political world asks whether Cain is to be taken seriously as a presidential contender, the answer isn’t obvious.

Matt Yglesias joked the other day he “can’t believe we’ve reached the point where I’m going to have to start doing hits on Herman Cain’s policy ideas,” adding yesterday:

Not that Herman Cain is going to win the GOP nomination, but can I just note for a minute how absurd it is that he’s doing well enough in the polls that those of us in the media need to pay some attention to what he’s saying and his ideas?

He’s not a real politician. He’s not a notably successful businessman. And most of all, he hasn’t spent any time learning about the issues.

To help prove the point, Cain said yesterday, “When they ask me who’s the president of Ubeki-beki-beki-beki-stan-stan I’m going to say, you know, I don’t know. Do you know?”

How presidential of him.

Part of the problem here is that it’s hard to be sure Cain is actually a presidential candidate, as opposed to being the head of a vanity exercise intended to sell books and line up a post-2012 media career. He’s not only failing to invest the time to learn the basics about public policy, he’s also spending very little time campaigning. The New York Times noted the other day that Cain arranged a “whirlwind trip through New York City” this week, which included some media appearances and power lunches, but Cain “did all but one thing — campaign.”

He doesn’t maintain much of a schedule — according to his public campaign calendar of events, “19 of the 31 days of October are blank” — and doesn’t bother raising a lot of money. Cain has hired staffers for key posts, but they have a nasty habit of resigning after being around the candidate for a short while. Cain hasn’t even bothered to put together any meaningful ideas for an agenda, other than the deeply silly “9-9-9” tax plan, which includes numbers that don’t come close to adding up.

This week, Cain even admitted he’s open to running as the GOP nominee’s running mate — the kind of thing real candidates simply never say, because they’re supposed to be focused on winning the nomination. Cain has also admitted that he’s considered ending his campaign more than once, and he planned to take time from his presidential bid to launch a separate book tour.

I can read the polls as closely as the next observer, but I haven’t seen much in the way of evidence that Cain deserves to be taken seriously.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.