WASHINGTON (AP) — Battered yet still popular after a bruising first term as president, Barack Obama raises his right hand Sunday to be sworn in for another four years as the leader of an America that is, perhaps, as divided politically and socially as at any time since the U.S. Civil War more than 150 years ago.

When Obama first took office as the 44th U.S. president, many Americans hoped the symbolism of the first black man in the White House was a turning point in the country’s deeply troubled racial history. Obama vowed to moderate the partisanship that was engulfing the country, but, four years later, the nation is only more divided. While Obama convincingly won a second term, the jubilation that surrounded him four years ago is subdued this time around.

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.

He faces fights with opposition Republicans over gun control, avoiding a default on the nation’s debts, cutting the spiraling federal deficit and preventing Iran from building a nuclear weapon.

Obama begins his second term at noon (1700 GMT) on Jan. 20, the date and time specified by law. He will take his oath in a simple White House ceremony. On Monday, he will repeat the oath and give his inaugural speech on the steps of the U.S. Capitol before hundreds of thousands of people. He then makes the traditional journey, part of it on foot, down Pennsylvania Avenue to the White House. Fancy dress balls, fewer than in 2009, consume the evening hours. Monday is also the holiday marking the birth of Martin Luther King, the revered civil right leader who was assassinated in 1968.

Joe Biden was sworn in for his second term as vice president shortly after 8 a.m. (1300GMT) on Sunday, taking the oath from Supreme Court Justice Sonya Sotomayor at his official residence at the U.S. Naval Observatory.

Before taking the oath himself, Obama and his family attended church services at the historic Metropolitan African Methodist Episcopal Church. Earlier, Obama and Biden laid a wreath at Arlington National Cemetery.

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.

Domestic issues, notably the economy and health care, dominated Obama’s first term, but there were also critical international issues that could define his next four years. Obama may have to decide whether to launch a strike against Iran’s nuclear facilities, something he is loath to do. Washington and its allies believe Iran is trying to build nuclear weapons. Iran says its program is intended for producing electricity. Obama has vowed to keep Iran from crossing the line to nuclear-armed status, but insists there is still time for diplomacy. But Israel is pressuring him to take military action sooner rather than later.

Obama will also have to deal with the civil war in Syria, Israel-Palestinian tensions, a chill in relations with Russia and a series of maritime disputes in Asia. The administration has long talked of making a “pivot” toward Asia after the U.S. has directed much of its energy to the Middle East in the past decade.

Yet the political battles at home continue to dominate Obama’s attention. He faces tough opposition from Republicans, especially from among its tea party wing — lawmakers determined to shrink government and reduce the taxes. Republicans are themselves divided between tea party loyalists adamantly opposed to compromises on taxes and spending and mainstream Republicans more open to negotiations.

A confrontation is brewing on the need for Congress to raise the limit on U.S. borrowing. Republicans now plan to avoid a fight in the short term, but they will raise the issue again before summer and will again demand steep spending cuts to reduce the government’s debt. Obama has said he won’t allow them to hold the nation’s economy hostage and will not negotiate, as he did in 2011. A failure to reach an agreement could leave the government without money to pay its debts and lead to the first-ever U.S. default or a government shutdown.

Beyond the debt-ceiling debate are other big budget fights. Looming in the coming weeks are automatic cuts to defense and domestic programs, originally scheduled for Jan. 1, unless Congress and the president act. And the U.S. budget runs dry in March, leading again to a potential shutdown unless both sides agree on new legislation.

Obama is also seeking new restrictions on guns and ammunition, a move opposed by most Republicans and the National Rifle Association, a powerful lobbying group which believes any limits would violate constitutional protections for gun owners. Obama was spurred to action by the massacre last month of 20 children and six adults at their school in Newtown, Connecticut. He has pledged to use “whatever weight this office holds” to fight for his proposals.

Among the second term’s other top-tier issues, immigration may be the one in which Obama enjoys the most leverage. That’s a dramatic change from his first term, when it was relegated to the background.

The White House is hinting at a comprehensive bill this year that would include a path toward citizenship for millions of immigrants now in the country illegally. Republicans, stung by heavy losses among Hispanic voters in the last two presidential elections, say they also want to revamp immigration laws.

Copyright 2013 The Associated Press.