In the hospital, after her Black Hawk helicopter was shot down in a fireball, L. Tammy Duckworth's fellow soldiers made sure four of her personal items made the trip home from Iraq with her: her wedding ring, her dog tags, her unit patch and a coin she always kept in the breast pocket of her flight suit.

To an outsider, the coin might have seemed like little more than a curious, poker chip-size trinket, designed with the emblem of her Illinois National Guard unit. To Duckworth, now an assistant secretary of veterans affairs, it was sacred: "That's my identity."

"Challenge coins," as they are known, have become an important part of the ethos of the armed forces, where the story of service members' careers - deployments, promotions, awards - is told by the ribbons and patches on their uniforms. Traditionally, commanders hand out the coins to troops for exemplary service and morale boosting. That's how Duckworth got hers. That's why it meant so much.

But in recent years, many outside the military have adopted the tradition, turning a sacrosanct ritual, some say, into a form of military chic that is now part of the Washington power game. The coin craze extends into almost every nook of the federal government. The secretaries of education, transportation and agriculture have coins. So does the EPA administrator, and even the Department of Agriculture's Office of Information Technology.

The coins have gone global - the Australian ambassador has one. And corporate: Boeing has a coin. So does Starbucks.

This coin creep is to some in the military an off-putting act of plagiarism that sullies the tradition. To others, it's a flattering statement of solidarity with those who serve.

"I don't see it as an offense," said Navy Capt. John Kirby, spokesman for Adm. Mike Mullen, the Joint Chiefs of Staff chairman. "I look at it as them wanting to associate with the sacrifice that the military is making."

But others fear that the coins have become more about vanity - both the giver's and the receiver's - than about service and sacrifice.

"They've become like an autograph. It's a thing to say, 'I met this person,'" said Todd Bowers, who served two tours in Iraq and one in Afghanistan with the Marine Corps and is an official at Iraq and Afghanistan Veterans of America (yes, the nonprofit group has a coin). "Now they're business cards."

In a town where status is conferred by much more than title - think of grip-and-grin-photos posted on recipients' ego walls, framed thank-you notes from politicians, appearances in book indexes and society pages - coins and who has them have become yet another means to measure, or inflate, importance.

On top, of course, is the president, who has laid his commander-in-chief coin at the graves of the fallen at Arlington National Cemetery. Soldiers have gone weepy after receiving a coin from the chairman of the Joint Chiefs.

Beyond the top brass, the massive Pentagon bureaucracy has joined in as well. The Air Force comptroller has a coin that says "Financing the Fight." The Army Force Management Support Agency's says "Documenting the Force."

Clayton Hinchman, a former Army captain who works at the Military Officers Association of America in Alexandria, keeps his coin collection on display at his office. Of all the coins he's received - including those from President George W. Bush and Vice President Dick Cheney - he cares most about two: One for graduating first in his Ranger school class, and one from a Navy explosive ordinance disposal unit he served with in Iraq. "I ate actual dirt with those people," he said.

As for those from more obscure bureaucrats, well . . . "I don't know if it's people wanting to feel good about themselves," he said. "I think it goes overboard when people view them as a collector's item. It's not. You're supposed to get them for sacrifice or meritorious service."

It is unclear how the coin tradition began, but the earliest one Jesse Medford, founder of the Challenge Coin Association, has ever seen was a 17th Infantry Regiment coin from the early 1950s. Special Forces units used them in the 1980s and the tradition slowly spread through the armed forces.

"It's been the last 10 years where it's spread like wildfire, definitely since the wars have been going on," he said.

In the past couple of years, the popularity of the coins has become "so vast that it's almost better to say who doesn't have a coin," said Adam Mulholland, owner of U.S. Challenge Coins, a Georgia manufacturer.

They're called challenge coins for a reason. Within the ranks, if someone challenges you, you're supposed to produce your unit coin on the spot. If you don't have it, you're indebted to the person who challenged you, which usually means you buy them a beer. If you do have your coin, they're buying.

Duckworth remembers a commander who never lost a challenge because he always made sure he had the coin. "He even had a coin attached to his soap box because his guys would challenge him in the shower," she said.

Another variation of the game is played at bars. When someone initiates a challenge, service members present their coins, and the person with the coin from the highest-ranking person drinks for free. But now with so many coins out there, the game can get confusing. Does the secretary of agriculture outrank the secretary of commerce? What about a civilian aide to the secretary of the army?

When he was covering the Pentagon for CNN, Jamie McIntyre kept getting "coined" by top officials after interviews, which made him slightly uncomfortable. "I always felt like as a news reporter, you don't want to be in anybody's debt," he said.

So he bought a batch of coins for $4 a pop with his own money because the network refused his expense account. "CNN Covering the World Since 1980," they read on one side. On the other: "Jamie McIntyre Covering the Pentagon Since 1992."

As the craze has taken off, the coins have gotten more elaborate - and expensive. McIntyre spent $6 a coin on his second batch, $7.50 on the next. The last batch cost $10 apiece, so he tried to be more discerning about whom he gave them to. But it had reached the point where it seemed everyone was handing out a coin.

"We're one step away from your neighbor giving you a coin for mowing the lawn," he joked.

The costs can add up. The office of the chairman of the Joint Chiefs of Staff spent $187,500 on 37,500 coins last year, according to a spokesman.

The Army doesn't appropriate funds specifically for coins, making it difficult to come up with a total cost. But the headquarters of its Training and Doctrine Command, which has 44,000 soldiers and civilians assigned to it, spent $27,000 on coins last fiscal year.

The Transportation Department spent $3,320 on coins last year. The Education Department spent $1,385. The Agriculture Department said it could not determine the cost of its coins, but said that, as with the other agencies, they are often handed out to military and law enforcement personnel as a thank-you.

Sen. John Barrasso (R-Wyo.), who uses campaign funds to pay for his coins, had never heard of them until he went to Iraq a few years ago and met Gen. David H. Petraeus, then the U.S. commander there, who coined him.

Barrasso learned that other senators take official Senate coins with them on overseas trips, so he decided to have one made. "More and more are doing this," he said.

Unlike the official (read: stuffy) Senate coin, Barrasso's is more Wyoming wild, with an image of a man riding a bucking bronco. He gives them out mostly to service members, he said. When he flies home on weekends, he always makes sure to have a few on hand, just in case he runs into soldiers at the airport. And he brings them when he visits troops abroad.

"They look at this, and it reminds them of home," he said. "And when you're halfway around the world, anything that reminds you of home is usually pretty welcome."