DES MOINES, IA — Bernie Sanders defended his call for raising Americans’ taxes in exchange for lower heath care costs, as he opened a candidate forum Monday night that served as a platform for Democratic presidential hopefuls to make a closing argument to voters one week before the Iowa caucuses.

“Yes, we will raise taxes,” said Sanders, an admission rarely heard in presidential campaigns. “We may raise taxes, but we are going to eliminate private health insurance premiums for individuals and businesses.”

Sanders would replace the nation’s existing employer-based system of insurance with one in which the government becomes a “single payer,” providing coverage to all. It would eliminate co-pays and deductibles, and Sanders’ argues, bring health care spending under control.

A self-described democratic socialist, Sanders cast his governing philosophy Monday as one reflecting that “the right for economic security should exist.” But he sidestepped a question about whether his policies would mean an era of big government.

Sanders’ was the first of three candidates to address voters at the CNN town hall at Iowa’s Drake University. Democratic front-runner Hillary Clinton and former Maryland Gov. Martin O’Malley, who has struggled to gain traction in the race, were to appear later in the event.