It's not quite an endorsement. But it's about as close as it can be to one.

That's the best way to describe President Obama's reaction to the decision by Rhode Island Gov. Lincoln Chafee (I) to become a Democrat. Without saying he supports Chafee in what's expected to a be a contested Democratic primary, Obama welcomed his former Senate colleague and key political ally to the party with open arms.

"I’m delighted to hear that Governor Chafee is joining the Democratic Party," Obama said in a statement distributed by the Democratic National Committee. "For nearly 30 years, Linc Chafee has served his beloved Rhode Island as an independent thinker and leader who’s unafraid to reach across party lines to get things done. I enjoyed working with Linc when he was a Republican in the United States Senate, and I look forward to continuing that collaboration on the issues that matter not just to the Democratic Party, but to every American."

Chafee and Obama have a history together. In 2008, Chafee, a former Republican senator who became an independent after leaving office in 2007, endorsed then-senator Obama ahead of the Rhode Island Democratic presidential primary. In 2010, when Chafee was running for governor, Obama notably refrained from backing Democratic nominee Frank Caprio, who didn't take the decision well. Caprio said Obama could take his endorsement and "shove it," a remark he later said he regretted.

Chafee is expected to face a contested Democratic primary, and polls show he is unpopular. Treasurer Gina Raimondo and Providence Mayor Angel Taveras are expected to enter the Democratic race.

Without specifically saying he will become a Democrat, Chafee said he intends to announce his party affiliation Thursday morning.

Democratic Governors Association Chairman Peter Shumlin of Vermont welcomed Chafee, but said the DGA plans to support whichever candidate wins the Democratic nomination.

"We are excited to welcome Governor Chafee to the ranks of Democratic governors and look forward to enthusiastically supporting whoever emerges as the Democratic nominee in Rhode Island," Shumlin said in a statement.