And then there were four

Sen. Heidi Heitkamp (D-N.D.)
Sen. Heidi Heitkamp (D-N.D.)

After Sen. Bill Nelson (D-Fla.) endorsed marriage equality yesterday, I figured we might not see any additional progress, at least for a while. There were only six Senate Democrats remaining who haven't offered their support for same-sex marriage, but all six represent "red" states.

My assumptions, I'm pleased to report, were wrong. This morning, freshman Sen. Heidi Heitkamp (D) of North Dakota issued a statement endorsing marriage equality.

"In speaking with North Dakotans from every corner of our great state, and much personal reflection, I have concluded the federal government should no longer discriminate against people who want to make lifelong, loving commitments to each other or interfere in personal, private, and intimate relationships. I view the ability of anyone to marry as a logical extension of this belief. The makeup of families is changing, but the importance of family is enduring."

Almost immediately after Heitkamp's announcement, freshman Sen. Joe Donnelly (D) of Indiana published a statement saying he, too, supports equal marriage rights for all.

"In recent years, our country has been involved in an important discussion on the issue of marriage equality. While serving in the House of Representatives, I had the opportunity to act on a core belief of mine: we are a stronger country when we draw on the strengths of all Americans. I voted to repeal 'don't ask, don't tell' and was an original supporter of the bill that would make it illegal to discriminate against someone in the workplace because of their sexual orientation. It is also for that reason that I oppose amending either Indiana's or our nation's constitution to enshrine in those documents an 'us' and a 'them,' instead of a 'we.' With the recent Supreme Court arguments and accompanying public discussion of same-sex marriage, I have been thinking about my past positions and votes. In doing so, I have concluded that the right thing to do is to support marriage equality for all."

The two become the ninth and tenth Democratic senators to endorse marriage equality in just the last two weeks. Of the 55-member Senate Democratic caucus, only four opponents remain: Mark Pryor of Arkansas, Tim Johnson of South Dakota, Joe Manchin of West Virginia, and Mary Landrieu of Louisiana.

What's more, to follow up on what we discussed earlier, there are now 53 senators -- 51 Democrats and two Republicans -- who are on record supporting the right of same-sex couples to get legally married.

As a practical matter, there is no pending legislation for senators to vote on, so reaching this milestone doesn't have a real-world impact on the larger cause of civil rights, but as symbolic matter, it's still extraordinary, and would have been nearly impossible to predict just a few years ago.