President Barack Obama on Tuesday promoted his plan to scale back spending without slashing aid to education, energy and science, acknowledging to a town hall crowd that mounting deficits could inflict "serious damage" on the country.

In an appearance at Northern Virginia Community College in suburban Annandale, Va., Obama blasted Republican alternatives to deal with federal budget problems, while at the same time predicting the two deeply divided parties would ultimately find a compromise on spending priorities.

"I'm optimistic. I'm hopeful," Obama said in his campaign-style outing. "Both sides have come together before. I believe we can do it again."

Obama's pitch came as his re-election bid is now under way in earnest. He is traveling across the country this week with a message that the government must reduce its staggering debt by cutting defense spending and health care costs, increasing taxes on the wealthy and protecting priorities he deems untouchable.

The president and House Republicans are vying for control of a suddenly surging national debt debate. Obama says his plan spreads the burden more fairly than a rival House Republican plan that would cut roughly the same amount of spending through budget cuts and an overhaul of the Medicare and Medicaid health care programs.