Crises have flared abroad in the last several weeks, in North Korea and Syria, just as public opinion surveys have shown a dip in Americans’ approval of President Obama’s handling of foreign policy.

Polls released in December and January found Mr. Obama’s net job approval on foreign policy (the percentage of Americans who approve, minus the percentage that disapprove) to be between plus-9 and plus-19 percentage points. In contrast, the last three major surveys asking about foreign policy, all conducted since late March, have shown Mr. Obama’s net approval on foreign policy to be barely above water, between plus-1 and plus-3 percentage points.

There may not be a single cause behind that decline. Mr. Obama’s record on foreign affairs — including ending the Iraq War, killing Osama bin Laden and ousting Col. Muammar el-Qaddafi, the Libyan dictator — was considered a strength during the 2012 presidential campaign.

But the current foreign policy landscape features more protracted problems: an unpopular war in Afghanistan, a stalemate over Iran’s nuclear program and an increasingly belligerent North Korea. In addition, an American intelligence assessment released this week found — “with varying degrees of confidence” — that chemical weapons had been used by the Syrian government, which President Obama had said would represent a “game changer” regarding United States intervention in the Syrian conflict.

In the months immediately following the November election, these long-simmering issues had been on the back burner of American politics as Washington focused on domestic concerns like the budget, an immigration overhaul and gun control. With international issues out of the national spotlight, Mr. Obama’s ratings on foreign policy may have lined up with his overall job approval ratings, which have averaged 49 percent approve and 47 percent disapprove. His approval on foreign policy now averages 48 percent. His foreign policy disapproval averages 46 percent.

But with the wider world forcing its way back to the forefront of American politics, the public’s evaluation of the Obama administration on foreign affairs may come into sharper focus, and may be influenced largely on how the situations in Iran, North Korea and Syria are handled.