By Bruce Stokes, Special to CNN

Editor’s note: Bruce Stokes is the director of Global Economic Attitudes at the Pew Research Center. Full survey results are available here. The views expressed are his own.

Foreign policy is the forgotten stepchild of the 2012 U.S. presidential election. At a time when the United States is engaged in the longest war in its history in Afghanistan, when in the eyes of foreigners U.S. stature as the hegemonic power is in question, and when a euro crisis could derail the American economy’s tenuous recovery from the Great Recession, voters choosing their next president are turning inward, preoccupied with domestic affairs to an extent unprecedented in recent times. Nevertheless, when the national security of the United States is seen as threatened by Iran or terrorism, voters remain aggressively internationalist.

Mitt Romney, in his speech accepting the Republican presidential candidacy, failed to mention the ongoing war in Afghanistan, the civil war in Syria or the legacy of Iraq. NATO, the principle U.S. security alliance, was ignored. There was scant reference to China. And the single mention of Russia was intended to show that Romney would be tougher than president Barack Obama in dealing with Moscow.

Obama devoted more time to foreign policy in his acceptance speech at the Democratic convention, reminding voters that he ended the war in Iraq, has set a withdrawal date for Afghanistan, has been tough with China and would not restart the Cold War with Russia. But he too made no mention of Syria or NATO.

Romney’s downplaying of foreign policy appears more in line with voter concerns this election season. Roughly eight-in-ten (83 percent) Americans now believe that the United States should pay less attention to problems overseas and concentrate on problems at home, according to an April Pew Research Center survey. Such isolationist sentiment is up 10 percentage points since 2002. And, for the first time, it is higher among Republicans (86 percent) than among Democrats (80 percent). But, in a sign of the partisan nature of this shift, while Democratic isolationism has fallen seven points in the last five years, it has risen 19 points among the GOP.

Going into the 2012 presidential election campaign, just 9 percent of Americans said they thought the president should focus on foreign policy concerns, 81 percent said he should preoccupy himself with domestic issues. Just five years ago, in 2007, 40 percent of the public put international issues at the top of their presidential agenda.

This domestic preoccupation is reflected in voters’ attitudes toward specific items on the next president’s international agenda.

Six in ten Americans think the president should remove U.S. troops from Afghanistan as soon as possible, according to an Pew Research Center survey in April. This includes 66 percent of Democrats and 62 percent of independents. Republicans are split – 48 percent supported removal and 45 percent backed keeping the U.S. troops in Afghanistan, possibly one reason Romney failed to mention the war in his acceptance speech.

Nearly two-thirds of Americans, meanwhile, say the United States does not have a responsibility to do something about the fighting in Syria, according to a Pew Research Center survey in March. And when asked more specific questions by CNN in mid-August, they opposed sending ground troops into Syria and were divided about establishing a no-fly zone or supplying Syrian rebels with arms. In contrast, in 2006, roughly half of Americans surveyed by the Pew Research Center said America should do something about the ethnic genocide in Darfur.

However, there is no such reticence to engage internationally and to use force when U.S. national security is deemed to be at stake.

When Romney said in his acceptance speech that “every American is less secure today because [Obama] has failed to slow Iran's nuclear threat,” he was touching a nerve he knew was sensitive.

About nine in ten Americans oppose Iran acquiring nuclear weapons, according to a 2012 Pew Global Attitudes survey. And, of those, 63 percent support the use of military force, if necessary, to deny Tehran a nuclear arsenal.

Similarly, three quarters of Americans support U.S.-led efforts to combat terrorism around the world. And 62 percent approve of the U.S. conducting drone missile strikes to target extremists in places such as Pakistan, Yemen and Somalia. This includes a majority (58 percent) of Democrats and nearly three-quarters of Republicans.

So, as Americans head to the polls this November, they are wary of new entangling foreign engagements. But such domestic preoccupation is not the same as passivity. Americans remain ready to use force in defense of U.S. interests.