WASHINGTON ― On foreign policy, President Obama effectively posted a sign on the White House lawn last summer that said: Come back after Election Day. Now, the moment has arrived and the world’s problems are lining up for Obama’s attention.

To manage the global problems coming at him, Obama will have to make decisions of the sort he sometimes deferred during his first term. The time is over for the cautious (if often sensible) approach that was dubbed “leading from behind.” Here’s a look at some urgent global issues intruding on the Obama victory party: 

― China is the biggest opportunity and danger ahead. A new leadership headed by Xi Jinping is taking over, but the shaky transition reminds Chinese and foreigners alike of the instability beneath the country’s glittering surface. Rising nations sometimes turn to nationalism as a way of maintaining internal cohesion, and this trend has been evident in Beijing’s push in the South China Sea. Obama’s response has been a “rebalancing” of military power toward Asia, but that’s only half the answer; diplomacy may matter even more.

Obama will be traveling to an Asian summit in Cambodia late this month. A stop in China won’t happen now (partly because of the uncompleted leadership transition) but it’s a priority for next year. The challenge is to build a dialogue with Beijing that can avoid the military confrontations that often arise when rising powers such as China confront already dominant ones.

Harvard’s Graham Allison suggests that Obama consider a version of what President John F. Kennedy called “precarious rules of the status quo” between the U.S. and the Soviet Union after the Cuban missile crisis. This involved regular dialogue about strategic interests, and an understanding that neither side would take provocative steps in the other’s backyard. Obama should sponsor a similar dialogue with China’s new leaders.

― Iran poses the biggest risk of war, and also the chance for a diplomatic breakthrough. Iranian Foreign Minister Ali Akbar Salehi and other would-be mediators have been floating trial balloons, but Obama wants confirmation that Supreme Leader Ali Khamenei supports such proposals. Another meeting of the P5+1 countries with Iran is expected within the next month; but the real negotiating may happen at the bilateral meeting both Tehran and Washington seem to want, which should happen sooner rather than later.

What’s the right formula for an agreement? Allison argues that the U.S. and Israel should stop dreaming about an ideal agreement and prepare for an “ugly deal,” like the one that ended the Cuban missile crisis. I agree with him that an acceptable “ugly” formula is one that verifiably stops Iran from having a bomb, and also from having the capability to break out toward weaponization faster than the U.S. can prevent it.

― Afghanistan is where bad news is almost certainly ahead. Obama talked during the campaign as if withdrawal of U.S. troops by 2014 was just a matter of putting them on planes. But the U.S. exit strategy is premised on Afghan security forces (ANSF) that can take over and avert a civil war ― and that’s looking increasingly dubious. An October report by the Pentagon’s special inspector general for Afghanistan reconstruction warned bluntly: “The Afghan government will likely be incapable of fully sustaining ANSF facilities after the transition in 2014.”

The missing element is a political transition to accompany the military drawdown. If Obama can’t create this political-military dynamic, his Afghan exit strategy will implode.

― The Middle East is where presidents make their legacies, and shed their tears. Obama faces three urgent problems: the metastasizing Syrian civil war, solidifying democracy in Egypt, and rehabilitating a broken Israeli-Palestinian peace process. These three areas show the limits of U.S. power ― as in last week’s failure to overhaul the Syrian opposition. But recovering from failure is part of the art of diplomacy in the Middle East, and that holds for Syria.

In dealing with Syria, Egypt and the Palestinian problem, Obama needs something that was too rare in the first term ― a round of secret contacts to build up the local players who can be America’s partners for peace. This means quiet contacts with everyone from Egyptian President Mohamed Morsi to the next Israeli prime minister (and with Israeli elections in February, that’s not necessarily Benjamin Netanyahu, who made a costly losing bet on Mitt Romney).

The sign at the White House says: Reopening for business. But first some quiet talks, and some strategic thinking about leading from the front. 

By David Ignatius

David Ignatius’ email address is davidignatius@washpost.com. ― Ed.

(Washington Post Writers Group)