It's official. Rhode Island Gov. Lincoln Chafee became a Democrat on Thursday, leaving behind the independent label he claimed after shedding his Republican skin in 2007.

How did Lincoln Chafee (R) morph into Lincoln Chafee (D)? The 43rd and 44th presidents were major factors. So was politics.

Chafee talks with the media after registering as a Democrat at City Hall in Warwick, R.I., on May 30. (Joe Giblin/AP)

The son of moderate Republican John Chafee, who served as senator, governor and Navy secretary, the younger Chafee succeeded his father in the Senate in 1999. Lincoln Chafee was appointed to the seat upon his dad's death, and won a full term in 2000.

But it wasn't long before he soured on the national Republican Party and its leader, then-President George W. Bush. In 2001, he opposed Bush's $1.35 trillion tax cut. In 2002, Chafee was the only Republican senator to vote against a resolution authorizing the U.S. to attack Iraq. In 2004, Chafee, who was already toying with leaving the GOP, said Bush's tenure in office amounted to "an agenda of energizing the far-right-wing base, which is divisive."

Despite the political distance Chafee sought to put between himself and Bush, he wasn't able to avoid being swept away in the 2006 Democratic wave election, falling to Democrat Sheldon Whitehouse.

After leaving the Senate, Chafee officially left the Republican Party to become an independent in 2007. He also wrote a book titled "Against the Tide: How a Compliant Congress Empowered a Reckless President."

In the 2008 presidential election, Chafee latched on early to President Obama, then a senator with whom Chafee had served. Chafee offered his endorsement in the lead-up to the Rhode Island Democratic presidential primary, something that would not be forgotten when Chafee later sought to resurrect his own political career.

That effort came in 2010, when Chafee joined an open race for governor as an independent with more natural appeal to Democrats than Republicans. Because of his relationship with Chafee, Obama declined to endorse Democratic nominee Frank Caprio, prompting Caprio to say the president could take his endorsement and "shove it."

Chafee narrowly won, and was back in the political mix once again. He kept up his support for Obama, even speaking at the 2012 Democratic National Convention.

Nowadays, Chafee is one of the nation's most unpopular governors. Poll after poll has shown that his reelection odds are pretty dim. Facing a bleak electoral picture, Chafee again changed his party affiliation.

Chafee told reporters his switch was motivated by the tone of the national Democratic and Republican parties. But as we've often noted in this space, it's impossible to separate personal politics from big decisions like these.

Chafee is wagering that winning what could be a tough three-way Democratic primary will prove less difficult than winning a difficult three- or four-way general election. We'll find out in the coming months how politically wise the move proves to be.

It's hard to imagine that Chafee would have made the jump if not for his relationship with Obama, and the advantage that connection could provide in a Democratic primary. Obama didn't endorse Chafee on Wednesday, but came awfully, awfully close. “I’m delighted to hear that Governor Chafee is joining the Democratic Party,” Obama said in a statement.

As we wrote Wednesday, Chafee's political survival instinct appears to be the overarching factor in his latest switch. But regardless of the outcome of the election, Chafee probably has made his bed for the rest of his political career. Switching in one direction is one thing -- doubling back would be virtually impossible to justify, even for a pol who has now had three different capital letters behind his name and lived to tell the tale.