The governing body for the National Education Association voted Monday to endorse President Obama for reelection in 2012, handing him an early campaign boost despite widespread dissatisfaction among teachers about federal education policies.

Dennis Van Roekel, president of the 3.2-million-member union, said in a statement that Obama shares the group’s vision for America. “He has never wavered from talking about the importance of education or his dedication to a vibrant middle class,” he said.

The endorsement from the nation’s largest union is one of the first from organized labor, traditionally a key source of votes and campaign volunteers. Many teachers are worried about the prospect of a Republican in the White House, particularly as their rights to organize are being challenged by GOP lawmakers in Ohio and Wisconsin.

Still, in the days leading up to Monday’s vote, many of the 9,000 educators at the union’s annual convention in Chicago said they were unhappy about the president’s promotion of charter schools and accountability policies that they say unfairly penalize teachers.