The U.S.-led war in Afghanistan is still going, too, after more than 11 years. The United States and its partners plan to end the war at the close of 2014. The president must decide when and how to pull home the 68,000 U.S. troops who remain and whether to cut a deal with the Afghan government to leave some lasting U.S. military presence after that.
At home, the presidential winner is likely to find struggles with Congress. Obama, the Democrat, is almost certain to be contending again with a Republican-led House. Even if voters choose Romney, they may well keep the Senate in control of Democrats, which would limit his legislative agenda.
Indeed, the basic state of Washington politics is broken.
The next president will inherit that problem, which is often beyond the president's ability to fix despite campaign promises, as Obama and Republican George W. Bush before him found.
Should the election be as close as polls suggest, the president in 2013 will be leading a nation in which about half the people voted against him. Most states are so decidedly Democratic or Republican they were not even contested this year. In a country built by dreamers, hope and optimism are sagging.
The impending fiscal crisis will have a cascading effect on the next presidential term.
How it is resolved will shape the chances of serious change ahead on tax law and entitlement programs such as Medicare.
January is on pace to bring across-the-board spending cuts of $109 billion, which, in real terms, would undermine the military and the core functions of government. The cuts were never intended to take effect. They were an onerous incentive for lawmakers to reach a broad deficit-reduction deal, but that never happened.
The fiscal cliff also gets its name from a series of expiring tax cuts. Romney wants to extend all the Bush-era tax cuts. Obama wants to extend them only for individuals making less than $200,000 and married couples making less than $250,000. The new president also will have to get Congress to increase the debt limit again to avoid a crippling default.
The debt is now above $16 trillion, with cries from every corner to reduce that figure or risk a choking of the economy.
It's one of the best-known challenges awaiting: The unknown. A drought, a bridge collapse, a mass shooting, a major oil spill.
It will be the job of the next president of the United States, ultimately, to handle everything.