On Martin Luther King Jr. Day, the day before his swearing-in, President Barack Obama’s inaugural committee stimulated a more than doubling of volunteer activity around the country.

[IMGCAP(1)]It was a demonstration of a major development that’s likely to unfold in the Obama era — a quantum leap in both paid national service and volunteer citizen service.

What Obama’s predecessor, President George W. Bush, referred to as “the armies of compassion” may at last be mobilized in huge numbers to tackle the country’s social problems — and on a cost-effective basis, at that.

The centerpiece of the process will be passage — its advocates hope, in Obama’s first 100 days — of the Serve America Act, sponsored by Sens. Edward Kennedy (D-Mass.) and Orrin Hatch (R-Utah), to expand Americorps, the nation’s civilian service force, from 75,000 personnel to 250,000 per year over five years.

Earning $12,500 a year, plus a $4,700 scholarship, Americorps volunteers do direct service at low-income schools, clinics, boys and girls clubs, environmental projects and disaster sites, and help organize the work of around 60 million unpaid volunteers.

Service Nation, a coalition of 120 mainly nonprofit organizations, hopes that by 2020, the government will give stipends to a million volunteers, whose efforts can leverage unpaid work by 100 million people.

Whether such an ambitious goal ever gets realized, it’s clear that Obama is moving the idea of national service — in fact, of citizenship — to a whole new level.

Partly, it’s the result of a coming-to-pass of the poignant challenge issued by President George H.W. Bush in 1989: “From now on in America, any definition of a successful life must include serving others.”

That’s an attitude that caught on among young people even before Obama appeared on the scene, as exemplified by Teach for America, the nongovernmental corps of lowly paid volunteer teachers that now has 37,000 applicants for 5,000 positions each year.

Another group, City Year, which puts recent high school and college graduates to work in poor neighborhoods, has experienced growth of 180 percent.

Dozens of other such nonprofits have grown up in recent years, and there’s an added overlay of “social entrepreneurship,” the idea that charities should use business techniques to measure their effectiveness and leverage their effect.

The Obama presidential campaign was powered, in part, by this combination of idealism and practicality.

Instead of volunteering in inner cities, tens of thousands of citizens went to work ringing doorbells and manning phone banks.

And shrewd organizers assembled a gigantic database of e-mail addresses and textable phone numbers that served as a potent political tool in the campaign.

As a result, the Obama campaign became a citizens’ movement of millions.

In advance of Martin Luther King Jr. Day, those in the database got messages from Obama, Michelle Obama and inaugural co-chairman Colin Powell urging them to sign up through a Web site, USAService.org, for volunteer work on Jan. 19.

More than a million people did so — double those who signed up last year — and they worked on 12,100 official projects, compared with 5,000 last year.

Obama set an example by working at a shelter for homeless teens and visiting wounded soldiers while his wife helped assemble gift packages for troops overseas.

In perhaps the most eloquent portion of his inaugural address, Obama cited military service as the model for citizen service at home.

“As we consider the road that unfolds before us, we remember with humble gratitude those brave Americans who, at this very hour, patrol far-off deserts and distant mountains,” he said.

“They have something to tell us today … because they embody the spirit of service, a willingness to find meaning in something greater than themselves.”

It’s a spirit, he said, “that must inhabit us all.” And he added that “a new era of responsibility” refers not only to personal conduct, but to “duties that we have … to our nation and the world,” and that this “is the price and the promise of citizenship.”

Some Republicans worry — as well they might — that Obama is conflating service and civic duty with support for him and his program and that his mailing list can be turned into a powerful pressure group as well as a volunteer force.

That’s the way it is with movements — they have multiple uses. And the Obama movement is making use of digital technology the way Franklin D. Roosevelt once used the radio and John F. Kennedy used television.

Whatever political implications are involved, the national service idea now has — and should have — broad bipartisan appeal.

It has as Senate co-sponsors such conservative Republicans as Thad Cochran (Miss.), Roger Wicker (Miss.), Judd Gregg (N.H.) and John McCain (Ariz.).

Historically, too, the service idea is bipartisan, originating with Roosevelt’s Civilian Conservation Corps and followed by Kennedy’s Peace Corps, Lyndon Johnson’s VISTA volunteers and Bush 41’s Points of Light.

Bill Clinton created Americorps, which hyper-partisan Congressional Republicans tried to kill in 1995 and 2003, but George W. Bush kept it alive and even expanded it from 50,000 volunteers to its current 75,000.

Both Bushes and Clinton established White House offices to oversee service programs, which are also managed by the quasi-governmental Corporation for National and Community Service.

Obama reportedly intends to establish a White House office to coordinate not only service programs, but “social innovation” and technology — which presumably involves a 21st century take on volunteerism.

“Whenever there’s been an expansion of service opportunities, it’s been because of presidential leadership,” says Alan Khazei, founder of City Year and now head of Service Nation.

“We have every indication that Obama is going to give this the leadership it needs,” he said. Indeed, it’s a movement whose time has come.