(CBS News) DETROIT - Vice President Joe Biden told a gathering of more than 3,000 teachers on Sunday that Mitt Romney and fellow Republicans think that teachers are selfish.
"They characterize you as only caring about yourself," Biden said at the American Federation of Teachers conference. "But the fact of the matter is, I don't think they know you. I don't think [Romney] knows you."
The AFT speech was Biden's third address to a national union this month -- he earlier spoke to the national police union in Florida and the national firefighters union in Pennsylvania. In those previous speeches, he used similar language to make the case that Democrats are far more attuned to the concerns of the unions' constituencies.
The vice president suggested that Romney doesn't understand the sacrifices teachers make in their personal lives for the betterment of their students when considering the demands teacher unions make for higher wages and better benefits.
"How many other people have to do a difficult job and have to deal with that child from a broken home whose mother or father just got arrested?" Biden said to a resounding applause. "How many of you have to do that every single day, and so much more?"