Jill Biden, the vice president's wife and a longtime community-college professor, addresses the delegates. To the delight of the crowd, she said, "Being a teacher is not what I do, it's who I am."
Editor's note: This version adds a statement from the Romney campaign in Michigan.
DETROIT -- Vice President Joe Biden took a page out of his lesson plan from earlier this month and again told teachers Sunday they were "under full-blown assault" from Mitt Romney and his Republican allies.
On the third day of the American Federation of Teachers national convention at Cobo Center in Detroit, against the backdrop of a boisterous union convention, Mr. Biden lauded educators and blasted Republicans, much as he did July 3 before a large crowd of educators in Washington at the National Education Association's 91st representative assembly.
The vice president hammered Mr. Romney for his education-reform plan that includes allowing states to use Title I funds -- originally intended to help schools in disadvantaged areas -- to help students and their families pay for private schools.
"I'm not questioning their motivation, I'm questioning their judgment," Mr. Biden said.
The AFT and the NEA are both strong supporters of President Obama. The AFT solidified its support with an endorsement of President Obama moments after Mr. Biden left the room.
"I don't think people fully understand how much goes into your profession," Mr. Biden said. "What we see when we look at you … is we see educators, we see professionals, we see teachers, we see public servants who are under full-blown assault."
The moments leading up to Mr. Biden's entrance into Cobo resembled a campaign party more than a convention, as the delegates took a break to stretch but ended up clapping and dancing to songs such as "Get Ready" by the Temptations.
The vice president, his wife, Jill, and their granddaughter took the stage to chants of "Four more years."
Ms. Biden, a community college English professor, was almost as much of a crowd-pleaser as her husband.
"Being a teacher is not what I do, it's who I am," Mrs. Biden told the crowd. "I know all of you understand that. Like you, I see every day how important education is in the lives of all Americans."
Soon after the vice president began his comments, he was interrupted by about 25 protesters who had made their way into the hall carrying a banner, but they were drowned out by chants of "Four more years."
Police escorted them out, without resistance, as Mr. Biden ignored them and went on with his remarks -- initially about his wife's career as a teacher and her dedication to the classroom and students.
"My name is Joe Biden and I'm in love with a teacher," Mr. Biden said to thunderous applause from the union members.
The convention's third day doubled as a campaign rally with the majority of those attending wearing blue Obama/Biden 2012 T-shirts and sending up multiple chants for re-election. Seats inside Cobo came with free Obama/Biden campaign re-election signs.
Mr. Biden's criticisms of Mr. Romney and the Republicans drew cheers and applause.
"Unlike our Republican friends, we don't see you as the problem. We see you as the solution," he said.
The vice president listed several education spending bills that President Obama supported to put teachers to work that he said Republicans voted down or attempted to block. He also accused Mr. Romney and other Republicans of wanting cuts to education and other services in order to afford tax cuts for the richest Americans.
"We believe you rebuild a country from the middle out. They think it has to come from the top down," he said.
The vice president mentioned Toledo, along with other cities, in praising teachers for making sacrifices for the sake of children, drawing roaring cheers.
"It's you, it's not somebody else, when the school district runs out of money because of this God-awful recession they inflicted on you all; it's you, it's you who sacrificed for those contractual raises and you who makes other sacrifices to maintain full-day kindergarten," he said.
He also was critical of Mr. Romney for telling teachers in Philadelphia that "class size doesn't matter," and referred to President Obama's goal of having the highest proportion of college graduates on the planet by 2020. Mr. Biden later said "being the best-educated country in the world" would keep the nation safer.
The AFT represents teachers in the Toledo Public Schools. It bargains for 1.5 million teachers and is the nation's second-largest teachers union behind the 3.2 million-member NEA.
Melissa Cropper, president of the Ohio Federation of Teachers, was one of several delegates who urged an endorsement of President Obama and Vice President Biden.
"Mitt Romney thinks we need fewer teachers," she said. "Mitt Romney doesn't want to work with us; he wants to work us over."
Mr. Biden's visit to Detroit did not go unchallenged by Michigan Republicans, who organized a news conference earlier in the day. Additionally, some members of the GOP picketed in front of Cobo Center.
“Vice President Biden has once again doubled down on the same policies that have failed to fix our economy and help the middle class," Sean Fitzpatrick, Romney Michigan campaign spokesperson, said in a statement today. "Instead of putting students first, this administration has put the union bosses that fund their political campaigns ahead of what’s best for our children. Instead of creating good jobs for graduates, this administration has presided over one of the worst jobs markets for young people."
Contact Ignazio Messina at: firstname.lastname@example.org or 419-724-6171.