Morning Joe blog - Education Secretary Arne Duncan: I believe in same-sex marriage Carolyn Kaster / AP Education Secretary Arne Duncan Vice President Joe Biden's declaration Sunday on "Meet the Press" that he's "absolutely comfortable" with gay marriage continued to reverberate Monday. On Morning Joe, U.S. Secretary of Education Arne Duncan echoed Biden. Asked by TIME's Mark Halperin whether he thinks same-sex couples should be legally allowed to marry, Duncan said flatly: "Yes I do." "Have you ever said that publicly before?," Halperin wondered. "I don't think I've ever been asked publicly," Duncan replied. Forty-nine percent of Americans agree with Duncan and Biden on the issue, according to recent polling. That number has risen sharply in recent years. The Morning Joe panel contrasted Biden and Duncan's stance with that of their boss, President Obama, who does not favor same-sex marriage, but has said his views are "evolving." That's not enough for many backers of gay marriage, though. Before Duncan's appearance, the Morning Joe gang was joined by Politico's Jim VandeHei, who said the gay-rights community is frustrated that Obama hasn't yet come out in full-throated support for what they call marriage equality. "They want him to come out and unequivocally state that he's for gay marriage," said VandeHei. And that's why there's been frustration from gay-rights activists since the beginning of the administration. Most observers think Obama personally has no problem with same-sex nuptials. So why won't he take the leap, asked Willie Geist? VandeHei admitted to being stumped. "I don't really think that the politics are that tricky for him any more," he said. But Joe Scarborough said the president likely has his eye on southern swing states like Virginia and North Carolina, where backing gay marriage could motivate social conservatives to turn out in droves against him. "You want to engage conservative Democrats, conservative independents, conservative Republicans?" asked Scarborough. Then put this out there. Halperin agreed, and said it's not just the south. "I would add Ohio to that list," he said. And Wisconsin, and maybe Iowa. Watch the clip below: