Photo by Christian Witkin/TIME

Universal national service – the notion that everybody who wants to serve the country or the community should have the opportunity to do so – is getting a surprising amount of attention on the presidential campaign trail.

Time magazine queued up the issue with a cover story last summer, and now several leading candidates have embraced it.

Barack Obama raised the ante this month with a speech in Iowa calling for a large expansion of national service, declaring, “This will be the cause of my presidency.” John Edwards is expected to follow suit and Hillary Clinton, Chris Dodd and Bill Richardson highlight service in their policy planks as well.

And it’s not only Democrats who are pumping the possibilities: Republican Mitt Romney once served on the board of City Year, one of the models for AmeriCorps, and his former firm, Bain Capital, has been a City Year backer.

Even more refreshing, nearly all the plans call for greater opportunities not only for young people, but for older adults as well. Such national service – through programs such as Peace Corps, Senior Corps or Experience Corps – can be a way to try out an encore career before making a longer-term commitment.

In a speech in Iowa, Obama called for expansion of AmeriCorps from 75,000 slots to 250,000 and the establishment of five new “corps” within the program: Classroom Corps, Health Corps, Clean Energy Corps, Veterans Corps and Homeland Security Corps. Obama also called for expansion of the Peace Corps to 16,000 volunteers – double today’s size though still a far cry from President Kennedy’s original vision of 100,000.

Obama’s plan specifically called out the contribution of boomers, calling for expansion of Senior Corps programs and of VISTA. “Experience Corps is a good model that should be expanded beyond reading and and mentoring to other challenges on which national service will be focused,” his proposal said, adding that he would seek additional income security, including continued health care coverage, for people who participate in citizen service.