(CNN) - President Barack Obama, who was largely quiet on the recent teachers strike in Chicago, said in an interview that aired Tuesday he was glad the issue had been resolved and took aim at Mitt Romney's approach to the situation.
"Governor Romney and a number of folks try to politicize the issue and do a lot of teacher-bashing. When I meet teachers all across the country, so devoted and dedicated to their kids, and what we've tried to do is actually break through this left-right, conservative – liberal gridlock," Obama said on NBC's "Today."
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The Chicago Teachers Union last week voted to suspend its strike that delayed the start of the school year in the city's public school system by eight days. Their protest was sparked by objections to a longer school day, evaluations tied to student performance and job losses from school closings.
In a statement last week, Romney criticized the union leading the strike, saying teachers were turning their backs on hundreds of thousands of children. The Republican presidential nominee also blasted the president for supporting the union, though Obama had not commented on the situation at the time.
Romney asserted that the president had "chosen his side in this fight," pointing out that Vice President Joe Biden told a teachers' union in 2011 "you should have no doubt about my affection for you and the president's commitment to you."
The two presidential candidates have long been at odds over some aspects of education policy, with Romney claiming Obama is too concerned with placating teachers' unions, which are major sources of Democratic campaign cash, and Obama saying Romney is wrong on his position that smaller class sizes aren't necessarily advantageous to better learning.
In the interview Tuesday, Obama continued his attack, painting Romney as a threat to teachers.
"I just really get frustrated when I hear teacher-bashing as evidence of reform. My sister is a former teacher, and I can tell you that they work so hard," Obama said.
In the final deal reached to end the strike, the union settled on a 17.6% pay raise over four years, down from the 30% initially sought. But it also got rid of the merit pay program that would have evaluated teachers on student test scores.
Obama, in the interview, suggested he disagreed with the scrapping of the merit system and argued reform should include performance-based changes.
"What is absolutely true is if we've got a bad teacher, we should be able to train them to get better, and if they can't get better, they should be able to get fired," the president said.
Romney's campaign responded to the president's comments, saying Obama puts politics ahead of education.
"Instead of reforming education and putting achievement in the classroom first, President Obama has put politics and his allegiance to the teachers' unions ahead of students," campaign spokeswoman Amanda Henneberg said in a statement. "When Mitt Romney was governor, Massachusetts' schools had the best test scores in the entire country and his leadership expanded opportunities for high-achieving students. As President, he will stand up for students, not special interests, and work to ensure that every child has access to a great school, great teacher, and a quality education."
- CNN's Kevin Liptak and Michael Pearson contributed to this report.