Gen. Douglas MacArthur had his signature corncob pipe. Soldiers got cigarettes in their C-rations during World War II. Even today, America's war on tobacco seems to have largely bypassed the military.

Now a proposal to make the forces smoke-free is drawing strong reactions from troops who have served in Iraq and Afghanistan, even though the Pentagon itself says any ban is a long way off.

The troops' fears — and, in some cases, hopes — were triggered by a study commissioned by the Pentagon and the Veterans Affairs Department that recommends moving toward a tobacco-free military, perhaps in about 20 years.

"Your nerves get all rattled and you need something to calm you down," said Staff Sgt. Jerry Benson of San Bernadino, California, with the 5th Stryker Brigade in southern Afghanistan.

Benson, a tall, thin redhead with a buzz cut, said his first attempt to quit smoking was foiled by stress from a roadside bombing in Iraq.

Defense Secretary Robert Gates seems to agree.

"He knows that the situation they are confronting is stressful enough as it is," said his press secretary, Geoff Morrell. "I don't think he is interested in adding to the stress levels by taking away one of the few outlets they may have to relieve stress."

He said Gates is not planning any ban, but is reviewing the study by the Institute of Medicine, which provides independent advice to policymakers, health professionals and the public, to see if steps can be taken toward having a smoke-free force some day.

U.S. military personnel and veterans interviewed by The Associated Press had strong opinions about life in the military without cigarettes, cigars and chewing tobacco.

Some said it would cut medical costs and make the force healthier, while eliminating smoking breaks would increase productivity. Others said it would dampen morale and reduce recruitment to the all-volunteer military.

Nearly all, however, said it was impractical and probably would never happen.

"It's an outrage," said Staff Sgt. Joe Dunn, 32. "I've been smoking for about 15 years and being forced to stop — not on my own terms — is something I'd have a hard time dealing with."

Dunn, of Gastonia, North Carolina, spoke during a cigarette break at the dusty Forward Operating Base Falcon south of Baghdad.

"I'm a fairly high-strung individual to start with," Dunn said. "If I were forced to quit, I'd probably be unbearable."

While smoking has declined in the U.S. civilian population, it remains high in the military despite various measures such as designating smoking areas.

In 2005, a third of the active-duty military smoked compared with a fifth of the adult U.S. population, the Institute of Medicine study said. Tobacco use in the military declined overall from 1980 to 2005, but is now reflecting the effects of the Iraq and Afghanistan wars.

Smoking rates among military personnel returning from both war zones may be 50 percent higher than among those not deployed, according to the study, which argues that the military has not tackled the problem as a priority.

To the troops who say smoking relaxes them, Ellen Hahn, an expert, explains that their stress is also a result of tobacco, because nicotine acts as both a stimulant and a depressant.

"For people who are in stressful situations much like the military, if you haven't had a cigarette in two hours, you're going to feel stressed out and irritable, and it's mostly because of the withdrawal," said Hahn, a professor who runs the University of Kentucky's Tobacco Policy Research Program.

"Nicotine is one of those drugs that both stimulates you and calms you down when you need it," she said.

So smoking does ease stress, but also creates it, she said.

Smokers are easy to find at the Falcon base, perched on railings in the designated smoking areas, using soft-drink cans for ashtrays.

"Smoking has been proven bad for your health, but it's a choice. It's not illegal. Drunk driving is illegal," said Air Force Staff Sgt. Alexander Roehm, 23, of Cincinnati, Ohio, who smokes 10 to 20 cigarettes a day and also chews tobacco. "Look at the movies. Smoking is one of the things you always see with Vietnam and World War II films. In World War II, smoking was a big thing. My grandpa used to say that cigarettes were one of the big things that they were real happy to get. It was just something to do."

Inside a smoke-free building at the base, however, Maj. Mathew Fitch, engineer for the 30th Heavy Brigade Combat Team, was cheering the prospect of a smoking ban.

The 40-year-old nonsmoker said cigarettes not only impair a soldier's health, but burn up productivity because every hour or two, somebody goes out and rounds up buddies for a puff.

"A smoke break can be a 20-minute affair," said Fitch, of Charlotte, North Carolina.

At Kandahar Air Field in southern Afghanistan, cigarette butts litter a courtyard.

Army Staff Sgt. Bob Flores, with the 5th Stryker Brigade from Fort Lewis, Washington, said he and his wife have agreed to quit together — pushed by their 8-year-old son — but only when he gets home.

"It's not the best time now — the stress of being here, and her being home alone," he said.

Tobacco costs the Defense Department more than $1.6 billion a year in medical care and lost work days, while the Veterans Administration has spent more than $5 billion to treat veterans for tobacco-related illnesses. Both have been working for years to reduce smoking among soldiers and vets.

The Pentagon laid out a plan in 1999 to reduce smoking rates by 5 percent a year by 2001 — and couldn't achieve the goal. Meanwhile, military commissaries still sell cigarettes at heavily discounted prices.

The military has, however, imposed some restrictions.

Tobacco use is barred during basic training. Several service branches also prohibit indulging while walking in uniform. Indoor smoking areas must have air extractors.

Even some tobacco consumers think a complete ban would be good.

"I think it would help healthwise," said Army Spc. Zack Lindsay, 24, of Raleigh, North Carolina, who serves in Headquarters Company of the 30th Heavy Brigade Combat Team in Iraq. He said he stopped smoking, but still chews tobacco. "I stopped one for the other."

Army Spc. John Beall, 20, of Charlotte, N.C., who serves in Headquarters Company of the 30th Heavy Brigade Combat Team in Iraq, said he tends to light up when he's bored and when others are smoking around him. He said he wouldn't oppose a ban.

Ricky Wilkerson, 49, of Lebanon, Tennessee, is in a stop-smoking program at the Veterans Administration hospital in Nashville. His family farmed tobacco in Kentucky, but he didn't start smoking until he was a 21-year-old Army infantryman stationed at the Panama Canal. He thinks the military should ban smoking, yet admits there were times when he was happy to have a smoke to relax.

"You're in the maneuvers and you've worked hard all day and they said 'Stop, light 'em if you got 'em.' Everybody fired up a cigarette," Wilkerson said.

During his deployment in Iraq in 2005, Spc. Will Pike, 25, of Boston said his 3rd Infantry Division combat engineer company tried to ban smoking. He quit for five months, then started puffing again.

"Everybody went completely crazy," said Pike. "If you take it away from us entirely, you're going to have some very angry soldiers."

Jeanne O'Brien, 39, from Monterey, California, said smoking eased the stress of driving trucks in 16-hour convoys through Afghan terrain littered with roadside bombs.

Smoking helped her stay focused "instead of having my nerves take control," she said.

Injured in Afghanistan and retired, the former paratrooper says smoking helps with her post-traumatic stress disorder. "A lot of times instead of hitting somebody, I sit down and have a cigarette."

A nicotine hit may feel good, but scientists say its brain action probably makes post-traumatic stress worse in the long run.

A study last year by the RAND Corp. research organization estimated nearly 20 percent of military personnel returning from Iraq and Afghanistan, or about 300,000 people, have symptoms of post-traumatic stress disorder or major depression. Clinics treat both the disorder and addictions at the same time, but few do, it said.

However, getting the entire military to go cold turkey is wishful thinking, said John Fink, 43, of Dickson, Tennessee.

"They've been talking about this for over 10 years now. Nothing has ever happened," said Fink, a Navy veteran and employee at the VA hospital in Nashville. A ban would drive people out of the military, he said, and "the military can't afford to lose anyone."