While presidential hopefuls Hillary Clinton and Barack Obama compete for the Democratic nomination on the campaign trail, another silent battle is being waged on the fashion front.

It's a bidding war.

And the objects of desire are limited-edition T-shirts featuring the faces of Mrs. Clinton and Mr. Obama.

Fashion designer Marc Jacobs created the Clinton shirt to raise money for her campaign, which he also did when she ran for a second term in the U.S. Senate. This campaign's design bowed the week of Feb. 24 and is $35 at the Marc Jacobs acessories stores in Manhattan's West Village.

Contemporary artist and graphic designer Shepard Fairey created Obama "Progress" and "Hope" tees, 900 of which were given out free at Obama rallies late last year. New versions of the shirt are selling for $25 at Upper Playground stores in San Francisco, Portland, Ore., and London and at UpperPlayground.com.

But since the retail stores aren't accessible to everybody, people ranging from supporters to collectors have turned to the online auction site eBay.

"I think that people really want to wear their choice for presidential candidate on their back," said eBay pop culture expert Karen Bard. "It's almost like wearing your vote."

Over the past several weeks, she said, the Clinton shirt sold for an average of $65.58 and the Obama shirt sold for an average of $381.39.

Wednesday evening, four Obama shirts went for prices ranging from $29.01 to $41.01 with the number of bids ranging from nine to 15. A lone Clinton tee went for $67.07 with five bids.

"These are very interesting T-shirts," Ms. Bard said. "They're not your average T-shirts. They're more fashion-forward."

In another spin on candidate products, Caliornia-based CafePress has since January been tracking sales trends of its user-generated, election-theme products to gauge a candidate's public appeal at any given time.

The company said Obama-related product sales surpassed Clinton in January, and since then have acounted for 70 percent of candidate-related sales. Since the Ohio and Texas primaries, however, Obama sales have slid 12 percent and Clinton's have increased 8 percent.

In T-shirt sales, Obama purchases outstrip Clinton four to one. Obama also holds the edge in children's clothing, thong underwear and dog gear while Clinton leads in beer steins, boxer underwear and teddy bears.

On the GOP side, the products related to presumed Republican presidential nominee John McCain are about 5 percent of sales tracked. And, the company said, sales of Ron Paul and Mike Huckabee items were never red-hot.

What, if anything, could demand for candidate-specific merchandise predict about the outcome of the Democratic primary and this fall's general election?

Probably nothing, says Lew Irwin, professor of political science at Duquesne University.

"That would make for good conversation," he said, "but it would be difficult to predict an election outcome based on it. I think it is certainly a pop culture phenomenon. These days, candidates and electioneering have become so sophisticated, they're looking for every indicator they can to gauge what public opinion is."

That probably includes sales of T-shirts with their faces emblazoned on them, Dr. Irwin suggested.

"Candidates pay attention to things like this to glean what's going on with the electorate."