Editor's note: Gloria Borger is a senior political analyst for CNN, appearing regularly on CNN's "The Situation Room," "AC360°," "John King, USA" and "State of the Union." Watch her Thursday on "CNN Newsroom" at 3 p.m. ET and "John King, USA" at 7 p.m.
Washington (CNN) -- At this stage in a presidential campaign, there's always someone -- and sometimes it's more than one -- who flirts with running and thinks a few things, as in: Why not me? (I'm smarter than the rest of those clowns!) What's the worst that could happen? (I'll be in demand on the lecture circuit!)
My fill-in-the-blank (book, TV show) will be assured of take-your-pick (readers, ratings) and I will be rich.
Or, in Donald Trump's case, richer.
Usually, these candidates are, er, interesting to watch. GOPer Alan Keyes comes to mind, a conservative presidential wannabe in 2000 who once jumped into a mosh pit during the Iowa caucuses. Then there's Rep. Dennis Kucinich, a liberal Democrat who ran in 2004 and 2008, and who was once a wunderkind known as "the boy mayor" of Cleveland. (That would not be enough, however, to win Ohio.) Or Ron Paul (father and now roommate of son, Sen. Rand Paul), who caught on last time around as the antiwar Republican and who was, always, eminently quotable and good TV.
Speaking of TV, there's Trump.
At least these other men had things to say. Trump just seems to have things to sell. Actually, one thing to sell: himself.
It would all be very amusing (especially the parts where he has easy solutions to all of our problems, such as: What to do with Libya? Take their oil!) if he weren't so, well, Trumpish. By that I mean insufferable -- and not just because he's always the biggest bloviator -- but because he sized up a political situation and figured out how to exploit it. Like a business deal.
The reasoning is as follows: I need to run for president. I need to find a way to get my numbers up in the polls. (Immediately!) So I need to find an instant base of support. And where is that? Among the anti-establishment GOP wing, some of whom are Obama haters, willing to believe just about anything, but most of whom just want to stick it to the regular GOP folks who have betrayed the cause.
So how does a once-liberal (abortion rights? Nevermind) GOPer do that? He tells the world he can fix the deficit problem pronto, calls Obama the worst president ever and becomes a "birther." Deal done! Take it to the bank!
How sad for serious Republicans with real ideas. Just as party regulars were fretting over Sarah Palin and Rep. Michele Bachmann, now they've got Trump the birther. Just as the congressional Republicans were getting up a head of steam as seriously intentioned budget cutters, in walks the carnival barker sending detectives to look for Obama's birth certificate.
"Trump is desperately clawing to the ideological right and using his issue to define himself and his ideology," moans one GOP strategist. "It makes this birther thing a real issue, and that's not what we need."
But alas, it's what Republicans now have. In a way, they have only themselves to blame: While Republicans should have put an end to the birther nonsense at the very start, they stoked it. While a few (like Tim Pawlenty) have called it nonsense, others (Palin) have refused to let it die.
Just as with the "debate" about whether Obama is a Christian, they instead are happy to chant the mantra "I take the president at his word." That's keeping it alive, while trying to sound reasonable. And that's double talk that no one should accept from any politician. It's gives "cynical" new meaning.
Even so, there are some Republicans out there who would like to have a real debate with Obama about things called issues. And, for them, the Trump birther nonsense is worrisome for the party's prospects. Why? Because this is a conversation Republicans are having with each other, not the country.
"Anybody who believes the guy (Obama) wasn't born in this country is already voting for us," says another GOP strategist. "This takes the whole Republican discussion out of the mainstream."
Karl Rove, who knows how to win elections, is clearly miffed, calling Trump's bid a "joke." "If he wants to base his entire campaign upon whether or not Barack Obama was really born in the United States, that's his privilege. I just think that's a losing strategy."
Indeed, recent CNN polling shows that 74 percent of independent voters believe that Obama was born in the United States. Presumably, the birther issue is not among their top concerns.
In the meantime, the president gets to spend the next 18 months talking to independent voters -- which is where the election will be won or lost. And instead of focusing on jobs and the economy, Republicans are sadly engaged in a circular and distracting rant, speaking to no one but themselves.
No matter how this all turns out, Trump will hit the big casino. But he could bankrupt the GOP first.
The opinions expressed in this commentary are solely those of Gloria Borger.