The problem with today's Republican Party...

...isn't their field of candidates, weak as it is; it's the party.

Or, to paraphrase Andy Borowitz, "There's nothing wrong with the Republican Party that a completely different party wouldn't fix."

It reminds me of that old joke: How do porcupines make love? Answer: With great difficulty.

And that's also the answer to the question, How do political parties hold their coalitions together? With great difficulty.

Take Franklin Roosevelt, for example. He presided over a Democratic Party in the 1930s and '40s that consisted of big city bosses, farmers, labor unions, southerners, northern ethnics, intellectuals, liberals, socialists and even Communists (see: Hiss, Alger). (Kind of makes you wonder who wasn't in the Democratic Party.)

And what happened to this coalition when FDR died? It exploded like a can of snakes.

In 1948, three Democrats ran for president: Harry Truman, the choice of the party; Henry Wallace, the agrarian socialist; and Strom Thurmond, the Dixiecrat. Truman ended up winning, of course, because he had the good fortune of running against the "do-nothing" Congress and a lackluster opponent, Governor Thomas Dewey of New York, the little man on the wedding cake.

Oh, and that six percent GDP growth in 1948 didn't hurt either.

But the Democrats got crushed in 1952. Truman's popularity plunged and the party turned to Adlai Stevenson, the "egghead" governor from Illinois, who lost twice -- badly -- to Dwight Eisenhower, the war hero. Only after eight long years in the wilderness did the Democrats take back the White House -- barely -- and with more than a little help from Irish Catholic election judges in Chicago like my grandmother.

Fast forward to today's Republican Party. The coalition formed by Ronald Reagan in the 1980s -- big business, evangelicals, libertarians, southerners, blue collar "Reagan Democrats" and Cold Warriors -- may be on its last legs.

Absent a charismatic individual like FDR or St. Ronald to hold it together, the GOP has fractured into board room/country club types (Mitt Romney and Jon Huntsman), libertarians (Ron Paul), culture warriors (Rick Santorum, Newt Gingrich and Rick Perry) and foreign policy hawks (Santorum, Gingrich, Perry and Romney -- sort of -- but not Huntsman necessarily, and definitely not Paul). Whew! This is confusing.

So what happens to the GOP when Romney -- finally -- gets the nomination? Will Paul mount a third-party bid? If not, will his supporters back Romney, vote Libertarian or just stay home? And what about Newt's and the two Ricks' supporters? Will they be motivated to go out and campaign for the rich Mormon guy from Massachusetts?

Barring some unforeseen downturn in the economy, I expect President Obama will cruise to reelection in November. And whither the GOP? Unless another Ronald Reagan magically appears on the scene, it will be navel-gazing time -- for a long while.