In 2008, then-congressman Artur Davis of Alabama gave an effusive speech to second Barack Obama’s nomination as the Democrats’ presidential candidate, saying that as president, Obama would “lead and inspire the free world.”

Four years later, Davis is on a convention roster again. But now, he will be delivering a prime-time Tuesday night speech as a Republican and Romney supporter.

Davis says he plans to talk about Obama’s failure to unite the country and fix the economy. But the DNC released a video last week featuring extended clips from Davis 2008 speech that ends with this pop-up caption: “Artur Davis’s speech at the GOP convention isn’t about Barack Obama. It’s about Artur Davis.”

Related: Artur Davis takes on Biden

Charges of being a self-serving pol who is willing to do anything to advance his career have followed Davis since he entered politics a dozen years ago with a primary challenge against incumbent and former civil rights activist, Earl F. Hilliard (D-AL). He lost by a wide margin but easily defeated Hillard two years later, and went on to represent Alabama’s heavily-Democratic, majority black Seventh District.

Davis was a mainstream Democrat and the first member of Congress outside of Illinois to endorse Obama for president back in 2007. He began to separate himself from the president and congressional Democrats as he prepared to run for governor. Initially favored to win the Democratic primary, he alienated many blacks by voting against the Affordable Care Act and snubbing black political groups. Ron Sparks, the state’s white agriculture commissioner, won the nomination in a landslide.

He subsequently declined to run for reelection to the House Congress and became openly hostile toward the Democratic Party, refusing to campaign for or support the party’s nominee. He penned an op-ed saying that Sparks didn’t represent real change and was failing the test of creating productive plans for Alabama.

He relocated to Virginia, declared himself an independent and came out in support of voter ID laws, which voting rights advocates say disenfranchise people of color and the poor. Since announcing his switch to the Republican Party in May, Davis has hit the campaign trail for Romney several times and will top off his political conversion with an speech at the Republican convention on Tuesday.
Virginia Democratic consultant Mo Elleithee implies that Davis’s conversion is pure politics. Elleithee says that last winter Davis called him to explore running for office in Virginia as a Democrat.

Mark Kennedy, chair of the Alabama Democratic party, has dubbed Davis a sore loser.

“The only part of the electorate Artur Davis is giving a voice to are former candidates who lost their races and then go on to blame it on everyone but themselves,” said Kennedy. “Between his penchant for changing his party and positions regularly, and for not taking responsibility for his own actions, Artur Davis seems a great addition to the Romney campaign.”

Davis’ successor in the House, Terri Sewell, also piled on. “The recent political choices of the former congressman clearly indicate that, at best, he is out of touch, or even worse, he was never connected to the best interests of this district,” she said.

Political sniping aside, Davis apparently sees this as a necessary step in his political reincarnation. But does a party-switcher really have an electoral future in a party that has thrown out lifelong, conservative Republicans like Richard Lugar and Robert Bennett for being insufficiently pure? Perhaps he should seek advice from former Alabama representative Parker Griffith, who switched from Democrat to Republican and lost badly in the 2010 Republican primary. That’s one thing the two men have in common.