With a grueling campaign behind him, the newly re-elected President Obama has returned to D.C. to begin tackling the problems that face him in his second term. The first order of business is getting Republicans and Democrats in Congress to make a deficit-reduction deal to avert the so-called fiscal cliff, a string of tax hikes and spending cuts scheduled to drain $600 billion from the economy in the first nine months of 2013. Here are details on that and other challenges confronting Obama in the next four years:

1. Rolling back tax cuts for the rich
"Obama's victory positions him to claim a mandate" for pushing through his proposal to make the wealthiest Americans pay more taxes, say Kathleen Hunter and Roxana Tiron at Bloomberg News. He has been "emboldened by the election results," so his advisers expect him to launch a new push for his "balanced" reduction plan, which cuts as much as $100 billion in spending "while letting the George W. Bush-era tax cuts expire for top earners." Conservatives will dispute Obama's so-called mandate to do this, says Greg Sargent at The Washington Post, but "it does seem awfully clear that a majority of voters, in re-electing Obama, chose an approach to our fiscal problems that includes a bit more sacrifice from the wealthy — and rejected the argument that raising taxes on the rich will hurt the economy."

2. Immigration reform
"Comprehensive immigration reform will be the next big domestic item on the president's legislative agenda," says Juliette Kayyem at The Boston Globe. Latinos helped deliver Obama a second term, so, if he has a mandate to do anything, it's making our immigration policies more just. "Within the next two years, Democrats will push for a way to turn the 12 million undocumented workers into official guest workers." They'll also encourage more legal immigration of skilled workers, on the theory that "specialized workers can help stimulate the overall economy, creating jobs for people already here." It's a "win-win" for Obama and his fellow Democrats, since it will both satisfy their base and bait Republicans into doubling down on their reliance on "angry white guys," a doomed party strategy.

3. Iran and Israel
President Obama appointed a Mideast peace envoy, former Sen. George Mitchell, on his second day in office in 2009, says Mike Mount at CNN. "Four years later, Israelis and Palestinians are father apart from a deal than at any time in the decades-long peace process." Neither Palestinian infighting nor Obama's tense relationship with Israeli Prime Minister Benjamin Netanyahu has helped. As for Iran, "Obama's re-election may have bought him more time to find a diplomatic solution and restrain Netanyahu from launching an Israeli strike" to stop Iran's rogue nuclear program. Obama's tough sanctions are taking a toll and could force Tehran to negotiate. Israel's Deputy Foreign Minister Danny Ayalon says that, when it comes to stopping Iran from getting nuclear weapons, Obama "has international legitimacy against Iran, more than Romney would have had." Now he has the time to see if he can get it done. The clock is ticking.