A Southern Democrat defecting to the GOP is not news. A black Southern Democrat defecting to the GOP is pretty big news. A black Southern Democrat who was a member of Congress and a vocal supporter of President Barack Obama warrants a screaming headline.

Don’t look for the screaming headlines, but former Alabama congressman Artur Davis has announced he is leaving the Democratic Party, joining the Republican Party, and says he will likely vote for Mitt Romney in November.

Davis is black, but even in Congress he didn’t toe the Black Caucus line. He was an opponent of what has become known as Obamacare, and left his U.S. seat to run for governor of Alabama. According to Morgan Little’s Los Angeles Times piece:

“Davis, who represented Alabama’s 7th Congressional District from 2003 to 2011, was notably the first member of Congress outside of Illinois to endorse then-Sen. Obama’s 2008 presidential bid. And it was Davis who seconded the official nomination of Obama at the 2008 Democratic National Convention.”Both Republicans and Democrats are reacting along predictable partisan fault lines.

Republicans are touting Davis’s defection as another example (along with Newark Mayor Cory Booker, former Rep. Harold Ford, Jr., et al.) that Obama’s vision for America is too far to the left for clear-thinking Democrats.

Democrats, after pretending they can barely remember just who this Artur Davis is, have blamed his defection on hard feelings due to his rising political star having stalled. That is a difficult sell considering the career of one Barack H. Obama.

Davis is considering changing his voting registration to Virginia, a fact not lost on Virginia’s Republican governor, Robert McDonnell, who pointed out how powerful a Black Republican running for Congress could be in the Northern Virginia suburbs of Washington, D.C. Getting on the ballot to run against Jim Moran (D-VA) of Alexandria, or the seat in wealthy exurbs of the 11th Congressional District (now held by Democrat Rep. Gerry Connolly) in 2014 or 2016 would not be a heavy lift.

That’s in the future. In the present tension of the battle between Barack Obama and Mitt Romney for the presidency, Republicans will use Davis’s defection as further evidence that the political juggernaut that propelled Obama to the White House in 2008 has not only lost its steam, but may have dissipated entirely.A MoveOn.org plea for money this week indicated that support for ideological purity on the left has declined to the point where the group might have to “scale back or pull the plug” on some of its activities, according to the Washington Examiner.

The looming recall vote in Wisconsin has been a focal point of organizations like MoveOn.org. But the most recent Marquette University poll there has Gov. Scott Walker holding on to a 7 percent lead over his challenger, Tom Barrett.

The ethnic stumbling of Elizabeth Warren in her campaign against incumbent Scott Brown for the U.S. Senate seat in Massachusetts has turned what many thought would be a glorious march to victory into a long slog for the Democrats.

All that to say, Artur Davis might not be the tipping point in this year’s political see-saw battles, but he has certainly added more, and important, weight to the Republican side of the board.