barack_obama_64.jpgWASHINGTON (AP) _ President Barack Obama issued a powerful defense of government in his second inaugural address on Monday, laying down a detailed challenge to the deeply conservative political opposition in Congress and demanding moderation from those who “mistake absolutism for principle, or substitute spectacle for politics.''

Looking down from the U.S. Capitol on a flag-waving crowd of hundreds of thousand on the National Mall, the first African-American president asserted his determination to keep in place the social safety net for the poor, the ailing and the elderly.

As he launched his second term, Obama spoke with fire for the center-left political agenda that first carried him into the White House four years ago. Gone was the need to carefully walk the political center line as he looked to re-election. Back was a readiness to confront the conservative Republicans who regained majority control of the House of Representatives in the 2010 congressional election.

The battle lines have been drawn between Republicans who to reduce the spiraling U.S. deficit and debt by cutting government programs and Obama and congressional Democrats who insist that those programs must be maintained, if modified, and supported by higher taxes.

The president said Americans must make hard choices to reduce the deficit and debt. “But we reject the belief that America must choose between caring for the generation that built this country and investing in the generation that will build its future,'' he said.

The Republican opposition wants to target spending cuts on the federal Medicare health insurance for Americans at age 65 and Social Security pensions for older citizens _ programs created by Democratic presidents and cherished by the party.

Inaugural speeches are often short on specifics and polarizing issues and instead appeal to broad values. In laying out an ambitious program for his coming four years, the president used his inaugural address to urge the country to join him in tackling a vast array of problems, from slowing climate change to honoring the dignity of men, women and children around the globe.

“My fellow Americans, we are made for this moment, and we will seize it, so long as we seize it together,'' Obama said. He also marked a new direction in foreign policy as the U.S. prepares to pull troops from Afghanistan, ending the country's longest war.

“We, the people, still believe that enduring security and lasting peace do not require perpetual war,'' the president said outside the Capitol, looking out across a huge crowd of people jammed should to shoulder on the National Mall below.

He challenged those who favor aggressive use of the powerful U.S. military, calling them to remember the policies of presidents past.

“We are also heirs to those who won the peace and not just the war, who turned sworn enemies into the surest of friends, and we must carry those lessons into this time as well,'' said Obama, who is under heavy pressure from the right-wing leadership of U.S. ally Israel and powerful voices in Congress to launch military strikes against Iran's nuclear program.

Obama, who has become increasingly outspoken in favor of gay rights and same-sex marriage, referenced the gay-rights riots of 1969 in his inaugural address, classing them as a civil rights watershed along with key moments in the struggles for blacks and women. He said the nation's journey is not complete “until our gay brothers and sisters are treated like anyone else under the law.''

While he was officially sworn in Sunday, as required by law, the glitter of Inauguration Day _ the parade down Pennsylvania Avenue toward the White House, the night of balls, the ceremonial beginning of a new four-year presidential term _ still enlivened staid Washington. The celebration was pushed to Monday because Jan. 20 fell on a Sunday this year. That placed the grand ceremony on the U.S. holiday marking the birthday of revered civil rights leader Martin Luther King.

Obama _ the politician who rose improbably from a history as a community organizer in Chicago and a professor of constitutional law to the pinnacle of power, faces a nation riven by partisan disunity _ a still-weak economy and an array of challenges abroad.

The president also faces a less charmed standing on the world stage, where expectations for him had been so high four years ago that he was given the Nobel Peace Prize just months into his presidency. “Only very rarely has a person to the same extent as Obama captured the world's attention and given its people hope for a better future,'' the Nobel announcement in 2009 read.

Monday's events had less of the effervescence of four years ago, when the 1.8 million people packed into central Washington knew they were witnessing history. Obama is now older, grayer and more entrenched in the politics he once tried rise above. Officials said crowds were about half what they were four years ago.

As he enters his second term, Americans increasingly see Obama as a strong leader, someone who stands up for his beliefs and is able to get things done, according to a survey by the Pew Research Center for the People & the Press. The survey shows him with a 52 percent job approval rating, among the highest rankings since early in his presidency. His personal favorability, 59 percent, has rebounded from a low of 50 percent in the 2012 campaign against Republican Mitt Romney.

When the partying is done on Monday, it's back to business for a president who is leading a nation.

In light of the nation's troubled racial history, Obama's election to the White House in 2008 as the first black president was seen by many as a turning point. In his first inaugural address, Obama vowed to moderate the partisan anger engulfing the country, but the nation is only more divided four years on.

Obama guided the country through many crushing challenges after taking office in 2009: ending the Iraq war, putting the Afghan war on a course toward U.S. withdrawal and saving the collapsing economy. He won approval for a sweeping health care overhaul.

Yet onerous problems remain, and his success in resolving them will define his place in history.