President Barack Obama on Wednesday marked his 100th day in office at a townhall meeting in Arnold, Mo., where he said raising the payroll tax cap is the best way to help secure the future of Social Security.

Obama, who spoke about the nation’s retirement system in answer to a question from the audience, appeared to rule out accepting an increase in the retirement age, arguing that this would be a burden for workers. He added that “you could— cut benefits or “raise taxes,— but then he said “the best solution— would be to increase the payroll tax cap.

“For wealthier people, why don’t we raise the cap?— he said.

Obama indicated that he may have another of his White House summits — which have included experts, lawmakers, and stakeholders in various issues — on Social Security. But he noted that problems with Medicare are more urgent, using Medicare’s financial shortfalls as a hook to promote his drive to overhaul health care.

“We’ve got to have health reform this year, to drive down costs and make health care more affordable,— he said.

Obama’s trip to Missouri, a presidential battleground state, shows that, after some foreign travel earlier this month, he is continuing his practice as president of scheduling events in “purple— states he will need for re-election. Obama last week held an event in Iowa, another important state on his electoral map.