From Franklin D. Roosevelt and John F. Kennedy to Bill Clinton and George W. Bush, presidents and those who aspire to be president have long put forth calls for greater public service. Some found success, while others fell short of their lofty rhetoric.

Roosevelt formed the Civilian Conservation Corps and Kennedy created the Peace Corps with strong support and participation, while Clinton's AmeriCorps has never fully realized its full potential, hampered by funding struggles since its 1994 inception.

Still, as Sen. Barack Obama called for greater public service yesterday, some experts predict the potential now exists for programs seeking an expansion of volunteerism to succeed, despite a slumping economy and the nation being at war.

"This may be a moment in time that is different from when earlier calls did not prove that effective," said Stephen Goldsmith, a former Indianapolis mayor who is now chairman of the Corporation for National and Community Service.

Goldsmith, a Republican and professor at Harvard's Kennedy School of Government, said bipartisan support, serious societal problems and heightened interest in service among young people could offer new or expanded service programs the ability for growth not seen in decades.

He said surveys show today's youth is deeply attracted to service.

Obama yesterday outlined several proposals to boost service, both at home and abroad, during a speech in Colorado Springs.

"Loving your country shouldn't just mean watching fireworks on the Fourth of July," he said.

"Loving your country must mean accepting your responsibility to do your part to change it. If you do, your life will be richer, our country will be stronger."

In his speech at the University of Colorado campus, Obama pledged that enhanced public service and active citizenship would be a central cause of his presidency.

Clinton's AmeriCorps program, which recruits workers in exchange for an education stipend, has never quite caught on the way Kennedy's Peace Corps did in the 1960s and '70s.

Obama promised to increase AmeriCorps slots from 75,000 to 250,000 and pledged to double the size of the Peace Corps by 2011.

Presumptive Republican nominee Sen. John McCain of Arizona also supports an expansion of both programs and has stressed public service, including in the military during campaign appearances.

Obama repeated his pledge to boost the size of the active military.

But he also said the nation's future and safety depends on more than just additional soldiers.

"It also depends on the teacher in East L.A., or the nurse in Appalachia, the after-school worker in New Orleans, the Peace Corps volunteer in Africa, the Foreign Service officer in Indonesia," he said.

He said he would make federal assistance conditional on school districts establishing service programs and set the goal of 50 hours of service a year for middle and high school students.

For college students, Obama would set the goal at 100 hours of service a year and create a $4,000 annual tax credit for college students that would be tied to that level of service.