Former Mississippi Democratic congressman Gene Taylor wants his old job back. But he's going to have an "R" instead of a "D" in front his name this time around.

Allen Iverson had a sweet crossover. It's been harder to pull of in politics. (GIF via Yahoo Sports on Tumblr)
Allen Iverson had a sweet crossover. It's been harder to pull off in politics. (GIF via Yahoo Sports on Tumblr)

Taylor's not the first to try the switcheroo. Nor will he be the last. But as recent history has shown, it's no political panacea, and almost always, is a sign of desperation.

The conservative Democrat announced late last week that he will run for his old seat -- this time as a Republican. He said there is a need in Washington for people who will do the right thing "without putting political parties first."

Taylor's decision reflects the political landscape in the Deep South, where the Democratic Party once thrived but has been sharply marginalized as conservative Republicans have ascended to power in recent years. (Case in point: Rep. John Barrow (D-Ga.) is the last white Democrat from the Deep South in Congress.)

Taylor follows in the footsteps of other pols who have tried to reinvent themselves under a different banner in recent years. It hasn't been a surefire formula.

Sen. Arlen Specter became a Democrat in 2009 after it became clear he'd fall to now-Sen. Pat Toomey in a GOP primary. Specter had the support of President Obama but still lost the Democratic primary.

Parker Griffith went to Congress as a Democrat from Alabama before running for reelection as a Republican. He lost, then tried as a Republican and lost by even more. He's back to being a Democrat now as a candidate for governor. But he's not seen as a real threat to unseating Republican Robert Bentley.

Lincoln Chafee has worn three different hats in Rhode Island. He was a Republican senator who soured on the policies of George W. Bush and became an independent. Chafee had some success following his exit from the GOP, winning the governorship as a nonpartisan candidate in 2010. But faced with deep unpopularity in 2013, Chafee joined the Democratic Party in an apparent wager that his friendship with Obama, among other things, would help him win the party's nomination and spare him a general election challenge from the left. We'll never know how well that would have worked out since Chafee abruptly dropped his bid months later.

The most current example is former Florida governor Charlie Crist. He's currently running for his old job, but this time as a Democrat. Crist decided to run for the Senate in 2010 as an independent after it became clear he would not defeat now-Sen. Marco Rubio (R-Fla.) in the Republican primary. He lost badly.

In 2012 Crist lent Obama a helping hand on the campaign trail and even spoke at the Democratic convention. He announced his party switch in late 2012 after earning his stripes in the eyes of many party elders. He has gone out of his way to combat the notion that he is an opportunist by embracing populist, liberal Democratic positions in order to demonstrate his allegiance. Polls show him leading Gov. Rick Scott (R). But the race is far from decided.

So why has it been difficult to pull off the party defection? For one thing, popular candidates don't tend to do it. It's typically a move of last resort. And unpopular incumbents don't tend to make great candidates. Nor do those who have been booted from office before.

In addition, after switching sides, pols immediately open themselves up to charges that they lack core beliefs and only care about their survival. That's an obstacle Crist will have to overcome this year. Timing is also a factor. Crist's 2010 independent Senate bid came months after he ran as a Republican. As a Democrat in 2014, he's had more time to warm up to the party's voters.

Sometimes the switch works. Just ask former New York mayor Michael Bloomberg, who became a Republican to run for mayor then became an independent before winning a third term. Or Alabama Sen. Richard Shelby, who went from Democrat to Republican in the 1990s.

But the bottom line is crossing over to play for the opposing team is not a silver bullet. That's worth keeping in mind when looking at the candidacy of Taylor, whose opponent is already hitting him for being a turncoat.

"It took 25 years for my former Democrat opponent to make it into a Republican primary, and I welcome him to it," said Rep. Steven Palazzo (R-Miss.).