Elected policymakers like to do smart and popular things, but they don't like to be the last one to do a smart and popular thing, which is how bandwagon effects begin -- politicians see their colleagues do the right thing, and they hurry to join the club before it's too late.
Consider the last week in Democratic politics. Former Secretary of State Hillary Clinton endorsed marriage equality last Monday, and by the weekend, Sen. Claire McCaskill (D) of Missouri was on board, too. Yesterday afternoon, Sen. Mark Warner (D) of Virginia announced on Facebook that he supports marriage equality "because it is the fair and right thing to do."
And by the end of the day, the bandwagon had a new member.*
After remaining mum on the subject when asked about it last week, Sen. Mark Begich's office issued a statement Monday night from the senator supporting marriage equality.
"I believe that same sex couples should be able to marry and should have the same rights, privileges and responsibilities as any other married couple," the Alaskan senator said in what appears to be his first direct statement on the subject.
"Government should keep out of individuals' personal lives -- if someone wants to marry someone they love, they should be able to. Alaskans are fed up with government intrusion into our private lives, our daily business, and in the way we manage our resources and economy," he continued.
That appears to bring the new total of sitting senators who support marriage equality to 44 -- 43 Democrats and one Republican.
As Rachel explained on the show last night, the pro-gay-rights side of the marriage debate has "essentially totally captured the Democratic Party," with additional Dems getting on the right side of history all the time. Rachel added, "[H]onestly, if you talk to anybody who's taking these issues seriously, it is now officially inconceivable that the Democratic Party would, say, nominate a presidential candidate in 2016 who doesn't believe in equal rights for gay people. It is a settled matter in the Democratic Party."
* Update: Though Begich hedged recently about his position on marriage rights, Timereports that the senator actually endorsed gay marriage last year, in a statement to the Human Rights Campaign.