In past elections, the critical threshold for presidential candidates was the commander-in-chief test: whether Americans felt they could trust them with the nuclear codes, the 3 a.m. phone calls, and the lives of troops overseas. President Obama declared in the first presidential debate that he considered his most important responsibility to be keeping Americans safe.

But when it comes to where the candidates and their supporters have put their money in the television ad wars, foreign policy has disappeared almost entirely.

A new breakdown of the topics of presidential TV spots by Kantar Media, a private firm that monitors political advertising, shows how dramatically foreign affairs has fallen off the radar. In the general election so far, there have been 1.1 million references in ads to jobs, taxes, and budgetary and spending issues, and less than 30,000 references to international affairs and the wars in Iraq and Afghanistan. There have been more than 22 mentions of the job issue alone for every single mention of the Iraqi and Afghan wars.

What’s more, the candidates and other advertisers’ few references to foreign policy have largely been confined to a single issue for each party, with no back and forth between the campaigns. Of the 24,070 ads that have mentioned Iraq and Afghanistan, 99.6% were sponsored by the Obama campaign. All of the 2,024 references to international affairs were made in ads sponsored by Republicans—and many of these were by pro-Israel groups attacking the president’s policies.

For much of the year, the campaigns’ single-minded focus on economic and domestic issues mirrored the mood of the electorate. Over the summer, foreign affairs and wars abroad were all but invisible to the public: a CBS News poll in August found that only 2 percent of voters considered these wars to be the most important issue in deciding their vote for the presidency, and foreign and military issues disappeared entirely in a similar CBS News poll in early September.

But the concerns of the public have begun to shift overseas as recent events—notably the attack on the Libyan embassy and the angry anti-American protests that have swept across the Middle East—have taken center stage. Polls taken in late September by NBC News and Bloomberg showed that seven and nine percent of voters, respectively, had come to consider events in the Middle East and terrorism as the most important issues that were at stake.

Foreign policy is also set to assume a more central role in the final sprint of the on-the-ground presidential campaign. Today, Mitt Romney is giving what his campaign is billing as a major foreign policy address at the Virginia Military Institute in Lexington. In Thursday’s vice presidential debate, Joe Biden, the former chair of the Senate Foreign Relations committee, will go head to head with Paul Ryan, and likely seek to go on the attack over Ryan’s foreign policy credentials. The town-hall style debate on Oct. 16 will include domestic and foreign policy. Finally, on Oct. 22, Obama and Romney will meet for their final debate, which will focus entirely on foreign affairs.

All of this suggests that the relative silence that the Obama and Romney campaigns— and their super PAC and nonprofit allies—have maintained about foreign policy on the airwaves is likely to come to an end. It also raises questions about what foreign policy messages the candidates are likely to push as the election enters its critical final weeks. Will Romney and his backers pivot from Israel to Libya, and to the Obama Administration’s response to unrest in the Muslim world? Will the Obama campaign be reminding us of Osama bin Laden’s demise and Romney’s adventures abroad?

Initial volleys have already been fired, with two conservative groups currently running ads that accuse Obama of not telling the truth about the killings in Libya and skipping national security briefings. Just this morning, the Obama campaign released a harsh new spot criticizing Romney’s stumbles during his summer trip to England, Israel and Poland as “amateurish” and his response to the Libya crisis as dangerously inept.

Reporters—and fact checkers—should prepare themselves for the ad wars to begin finding ammunition overseas.

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Sasha Chavkin covers political money and influence for CJR's United States Project, our politics and policy desk. He has written for ProPublica, the Center for Public Integrity, and The New York World. Follow him on Twitter @sashachavkin.