Asked if teachers unions were slowing the pace of reform, Obama again dismissed the criticism — although he made clear that he had reservations about a tenure system that would not allow poor teachers to be removed from a classroom.
"You know, I just really get frustrated when I hear teacher-bashing as evidence of reform," Obama said. "My sister is a former teacher, and I can tell you that they work so hard… [W]hat 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."
Obama defended Chicago Mayor Rahm Emanuel — the former White House chief of staff — for his handling of the strike.
"It was very important, I think, for Mayor Emanuel to say let's step up our game, and it was important for the teachers unions also to say let's make sure we're not just blaming teachers for a lot of big problems out there," Obama said. "Let's make sure we've got the resources, so i'm glad it was resolved, but I do think that from the perspective of Democrats we can't just sit on the status quo or say that money's the only issue. Reform is important also."
The president went on to criticize Mitt Romney's education plan, saying ultimately the Republican budget would result in more teachers being fired and class sizes increasing.
"This is a big argument and a big difference that I've got with Gov. Romney in this election, because they talk a good game about reform, but when you actually look at their budgets, they are talking about slashing our investment in education by 20 percent, 25 percent," Obama said. "We've already seen 300,000 teachers that have been fired across the country, and as a consequence class sizes have gone up by 5 percent."
Romney's campaign reiterated its attack on the president in a statement later Tuesday.
“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," said Romney spokeswoman Amanda Henneberg. "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."
The president was appearing as part of NBC's "Education Nation" segment; Gov. Romney will appear later Monday on the show.
In a more lighthearted moment, the president admitted he had failed tests during school and was "a mediocre student" until getting to college.
"Malia and Sasha are so far ahead of me, basically in all respects," Obama said. "They are just better people than I was at their age, and they are doing wonderfully. You know, I couldn't be prouder of them. I will say that at least at the school they are at, they are getting a lot more homework than I did when I was that age. They seem to be working deep into the night, you know."