Rhode Island Gov. Lincoln Chafee (I) will soon announce that he will join the Democratic Party, nearly six years after he left the Republican Party to become an independent. Welcome to the world of party switching, which is more often than not these days motivated less by a principled change in beliefs than a last gasp attempt at political survival.

(Steven Senne/AP)

Chafee has been in rough political shape for some time, polls show. As an independent governor elected in 2010, Chafee faced the prospect of a race against Democratic and Republican nominees, as well as Moderate Party candidate Ken Block. Most analysts thought that race was unwinnable for the incumbent. (The Fix ranked Rhode Island as the second most likely governor's race to switch parties in 2014.)

Chafee's wagering that he stands a better chance of winning what is now expected to be a three-way Democratic primary -- with two strong up-and-coming candidates -- than he would have in the general election scenario described above. But even in the Democratic primary, Chafee faces an uphill climb. Treasurer Gina Raimondo and Providence Mayor Angel Taveras have been expected to run for some time, and there's no indication they'll step aside for the incumbent.

Chafee is not the first politician to make a party switch motivated almost entirely by a political survival instinct.

Then-Florida Gov. Charlie Crist decided to run for the Senate as an independent after it became clear he would not defeat now-Sen. Marco Rubio (R-Fla.) in the 2010 Republican primary. The late Arlen Specter of Pennsylvania switched his party affiliation from Republican to Democrat in 2009 to avoid a near-certain loss in the Republican Senate primary against Pat Toomey. Then-Rep. Parker Griffith of Alabama went from Democrat to Republican in 2009 in a similar attempt at political survival. All three fell short. And that doesn't bode well for Chafee.

Not all party switches are created equal, though. That's an idea with which Chafee should be intimately familiar. He left the Republican Party in 2007, and won as an independent candidate for governor three years later.

And Crist, who has long appeared to have been laying the groundwork for a political comeback, switched from being an independent to a Democrat last December, nearly two full years before the 2014 gubernatorial election that he is expected to enter and may well win.

The lesson may be to play the long game when it comes to party switching. But, Chafee does not have that luxury right now. We'll find out in the coming months whether his decision will be an example of deft dodge of near-certain defeat or whether his name will be the added to the ignominious list of politically-motivated party-switchers.