The auto bailouts, which worked better than even administration economists thought they would, helped Obama with blue-collar voters in key Midwestern states, particularly Ohio and Michigan. And bin Laden's demise was a singular achievement that deprived Republicans of a typical line of attack, that Democrats are weak on national security.

Obama also piled up huge majorities among black and Hispanic voters, outweighing Republican Mitt Romney's advantage among white voters.

A second term gives Obama an opportunity to separate himself from one-termers such as Jimmy Carter and George H.W. Bush, and go down as the type of president whose name is etched onto buildings. But this is merely an opportunity, hardly a guarantee. The recent history of second terms has been one of scandal or failure.

Obama goes in having already achieved what others, ranging from Harry Truman to Richard Nixon to Bill Clinton, failed at: enacting universal health insurance legislation. In his second term, this new law, which has been so reviled in some quarters, will go into full effect and Americans will judge it for themselves. Our guess is the opposition will fade with time as the benefits become more apparent, although cost-control will remain a challenge.

Also in the second term, the economy will likely improve, if for no other reason than it has had more time to heal from the Great Recession. Though control of Congress will remain unchanged, an improving economy could change the dynamic of Washington, pushing up approval ratings of both parties and forcing them to find other things to do besides blaming each other.

All appearances to the contrary, Obama and Republicans, who retained their House majority on Tuesday, are actually growing more dependent on each other.

They are both mindful of the ticking time bomb that they created with automatic tax hikes and spending cuts set to occur at year's end. Both realize that allowing this "fiscal cliff" to go into effect would benefit neither party. And both stand to gain from a bipartisan deal to prevent this, while also slashing trillions of dollars from projected deficits.

For Obama such a deal is a must, as he understands that his legacy will take a hit if he drowns future generations in debt. Obama's perceived indifference to trillion-dollar deficits year after year helped give rise to the Tea Party movement in 2010 and contributed to the closeness of this year's contest.

For Republicans, doing something about the deficit, rather than just using it as reason for criticizing Obama, would help restore their bona fides as a party of fiscal responsibility. Such a deal might even lead to progress on immigration reform and other needed legislation that has been gridlocked for years.

Obama came in with unrealistically lofty expectations in 2008, and he failed in his aim to bring about a post-partisan era in Washington.

His re-election, in a nation that remains sharply polarized, might be the cause for unduly low expectations now. But, if Obama and congressional Republicans are willing to compromise, there's reason to hope this election will be a catalyst for positive change.