When talking about the concerns that preoccupy voters in tough economic times, political analysts often turn to a well-worn phrase: bread-and-butter issues. It seems hard to dispute, then, that the cost of bread could end up playing a role in this year’s campaign for the White House.

Bread prices last month were up almost 15% over a year earlier, according to the Labor Department. Recent Agriculture Department numbers show bread costs rising at 2.6% a month, which works out to 36% if sustained over the course of a year. Some restaurants are now charging for the usual breadbasket, while others still dole it out free, but only upon request.

Prices for the main ingredient in most bread, wheat, rose steadily over the last nine months and spiked in February to more than double year-earlier levels. Wheat costs have since eased to about 60% higher than a year ago.

The hikes have caused protests, even riots, in countries ranging from Haiti to Afghanistan. Here in America, the reaction has been more muted, though there are signs that may be changing.

American bakery owners marched on Congress last month demanding some relief. Initially, the American Bakers Association asked to “curtail wheat exports until bakers and other domestic users are guaranteed the supplies they need.”

This week, a lobbyist for the group, Lee Sanders, said it is not calling for an all-out ban on shipping American wheat abroad. “We’re not asking for a moratorium, but what we’re asking for is for USDA to look at export programs and policies,” she said. “We’re just concerned. We don’t want to run out.”

This could be dismissed as mere whining from business owners about their costs going up. However, the scenes of food shortages and related unrest abroad are playing out night after night on the television screens of Americans already in a protectionist mood.

More voters will soon notice that the high cost of bread, flour, rice, and other commodities in America is due in part to countries such as Ukraine, Russia, Kazakhstan, and Argentina restricting exports with the goal of feeding their own populaces. Meanwhile, the collapse of the American dollar is making it dirt cheap for foreigners to buy out our supplies and whisk them overseas.

The notion that America’s amber waves of grain are being cleared out by foreigners while food prices surge here may be tough for the American electorate to swallow. Some talk show hosts are already picking up on it.

“The breadbasket of the world is burning through its food supply and it’s our leaders in Washington who are taking the food right directly out of your and your children’s mouths,” Glenn Beck declared on his CNN Headline News program Monday night. “For the first time in our history, we’re actually importing wheat. … Go to the store, please, and buy some food and then store it, please.” (I was a guest on the same show to discuss rice shortages at warehouse stores.)

Aides to senators Obama and Clinton met with the bakers last month, but asked yesterday about the calls for export limits, Mr. Obama’s campaign took a pass and Mrs. Clinton’s camp failed to respond. Since most farmers are profiting from the high prices, don’t look for either of the Democrats to say much on this subject before their primary fight on May 6 in Indiana, which has a large agricultural vote.

An economic adviser to Senator McCain, Douglas Holtz-Eakin, said voters are beginning to complain about food prices. “It’s a pretty big deal,” Mr. Holtz-Eakin said. “We understand why people are upset. There’s obviously a lot of stress about it.”

Mr. Holtz-Eakin said “a lot of the problem” can be traced to decisions to subsidize biofuels in an effort to limit global warming. However, he said Mr. McCain views export bans in America or other countries as a mistake that will worsen the crisis rather than improve it. “It’s very shortsighted,” the adviser said.

So far, the leading proponents of anti-trade sentiment in America have not tapped into the food price issue. But when Lou Dobbs gets around to it, the presidential hopefuls had better look out.