Gallup's latest poll further confirms a trend we've been seeing all year--Americans are growing more supportive of marriage equality, with 53 percent in support and 45 percent opposed. The shift is concentrated among Democrats and Independents, while Republicans have remained opposed in equal numbers as last year.
The fact that 70 percent of young people support marriage equality is also fantastic news for marriage equality in the long run, but in the long run I'm not sure how good the news is for Democrats. Polls don't measure salience of course, and just as Republicans have long overestimated their chances for gaining black votes by looking at polls showing most black Americans opposed to same-sex marriage, if you're a young person who thinks we need to privatize Medicare you're probably still going to end up voting Republican anyway.