Tim Johnson today became the latest Democratic Senator to embrace marriage equality. But each time a new Democrat joins that stampede — and especially when a (still-rare) Republican does — my question at this point is: what about ENDA?

That is, what about the Employment Non-Discrimination Act — which, in polling, is far more popular than marriage equality. There’s overwhelming support for making it illegal for employers to discriminate against employees on the basis of sexual orientation; in fact, most Americans assume it’s already illegal. But in most places, in no small part because ENDA hasn’t passed, that’s not true.

In the last Congress, the Senate version of ENDA had 43 cosponsors; the House version had 171. The new versions for this Congress are still being drafted, but when they are introduced, what are the new converts to the cause of marriage equality going to do? Only 40 Democratic Senators cosponsored it last time. Will Tim Johnson join them in the current Congress? Will the remainder of the 52 Democratic Senators who now support same-sex marriage? What about Rob Portman, and any future Republicans who flip?

It’s possible, and perhaps likely, that Supreme Court action will make marriage a moot issue for Congress, although if the court chooses not to, then legislative repeal of the Defense of Marriage Act will certainly be on the Senate agenda, at least. But ENDA is something that Congress will need to do; even if the Court and the executive branch prevent government discrimination, it will take a law to affect the private sector.

Is it realistic that ENDA could actually pass in this Congress? After the election in November, most observers would have said it wasn’t remotely possible. But with the ground shifting so fast, it doesn’t seem entirely far-fetched that a path similar to the Violence Against Women Act (win a bipartisan vote in the Senate, pass with mostly Democratic votes in the House) might be attempted. No one really expected ENDA to be high on the agenda of the 113th Congress, but right now anything is possible.