In an election cycle focused on jobs, campaign material made by foreign workers tends to become political kryptonite.

U.S. Sen. Richard Lugar's campaign learned that two weeks ago when a Republican operative began circulating a photo of Lugar's campaign shirts showing that they were made in El Salvador. Some clever photo cropping left out the fact that the shirt material was purchased from the U.S.

Indiana Democrats quickly pounced on Lugar's apparent stumble, and the Lugar team walked it back, saying they'd made a mistake. Although Lugar political director David Willkie said the shirts were purchased from an Indiana company, he said the campaign should have ensured they were stitched in the U.S.

"It was a mistake, it was an oversight. We are collecting any T-shirts (made in El Salvador) and removing them to be replaced by ones made in the United States," Willkie said.

Lugar isn't the only Republican catching criticism. When Indiana tea partiers gathered last weekend to endorse State Treasurer Richard Mourdock's primary challenge to Lugar, they sold T-shirts for $20 each to supporters. Those shirts, too, were made in El Salvador.

Monica Boyer, co-chair of Hoosiers for a Conservative Senate, the tea party coalition backing Mourdock, said hitting Lugar or any other campaign for buying paraphernalia made overseas seems "petty," largely because it is so hard to find goods made completely in the U.S. from U.S. materials.

"It would be great if we could purchase items in America," she said. "I don't know if you've ever tried to do that before. See, you just can't find them. It's a sad situation we're in. Preferably, we would like everything made in America."

The staggering economy and trouble transitioning between jobs makes free trade a hard sell politically, even though it is still better in the long run, said Homi Kharas, senior fellow at the Brookings Institution and deputy director of its Global Economy and Development program.

The flip side of losing low-paying manufacturing jobs is that Hoosiers gain jobs in businesses like Columbus-based engine maker Cummins, he said.

Kharas says anyone selling shirts made in El Salvador has an easy retort: "Would you rather have jobs in engine manufacturing or would you rather have people making T-shirts?"

"The deal with trade is you can't do both," he said.

But with Indiana unemployment at 8.7 percent in August and the national average staying high at 9.1 percent, even the smallest of purchases has to be made in the U.S., at least to avoid political slap shots while campaigning on a jobs platform.

President Barack Obama found that out this summer when conservatives blasted him for launching his American jobs tour through the Midwest in a tour bus made with Canadian parts.

The political fact-checking web site FactCheck.org reported in August that the Secret Service signed a contract with the Tennessee company Hemphill Brothers Coach Co. to pay $2.2 million for two specially made buses. The Tennessee company then outsourced some of that work to a Quebec-based company.

Of course, motor-vehicle manufacturing has long been an international endeavor. Hoosiers working at Indiana's Honda, Subaru and Toyota plants know that better than anyone. Lt. Gov. Becky Skillman led a trade mission last month to Japan to bolster those relations and hopefully bring more jobs back to Indiana.

Still, the domestic jobs shot is an easy, and popular one to take.

"Senator Lugar and the tea party might talk the talk, but only Joe Donnelly is walking the walk by buying American and fighting unfair trade deals that ship our jobs overseas," Indiana Democratic Party spokesman Ben Ray said last week.

Indeed, Obama has found himself largely at odds with congressional Democrats while considering a trio of trade agreements. President George W. Bush found himself in the same position in 2005 when lobbying for the Dominican Republic-Central American Free Trade Agreement, which liberalized trade with El Salvador and other Central American nations. Lugar voted for the trade agreement.

According to the U.S. State Department, DR-CAFTA gives "El Salvador preferential access to U.S. markets. Textiles and apparel, shoes, and processed foods are among the sectors that benefit."

As for Obama's American jobs tour bus, it was the North American Free Trade Agreement signed by President Bill Clinton in 1994 that liberalized trade between America and Canada.