They've been called the most-hated unit in the Army - the 1st Battalion of the 509th Infantry - known as the Geronimoes.

The Geronimoes are tasked with playing the "enemy" at the Army's Joint Readiness Training Center in Fort Polk, La., putting visiting infantry and special operations troops through their paces.

Recently, that has meant playing Iraqi insurgents and terrorists - an enemy whose rocket attacks and suicide bombings are killing U.S. troops and Iraqi civilians almost daily. To play the part, the men of the 509th were allowed to grow full beards and wear Iraqi civvies in place of their uniform.

Lt. Col. Casey Griffith, the commander of the unit, calls the 509th "the best bad guys I know, but also the best good guys I have ever known."

The bad guys now have to switch sides. With the Army pressed to rotate more soldiers into Iraq, they have now turned to the 509th, which hasn't been deployed in 60 years. Two of the battalion's four companies, Alpha and Bravo, have been called up for duty in Iraq.

"I think the Army said, 'Hey that's the 509th - those are Geronimoes. They're a historic unit. They're a well-trained unit, a highly disciplined unit. We need somebody right now and those guys are ready,' " said Griffith.

So the notorious "bad guys" have had to shave their beards, put on an Army uniform, and become regular soldiers again. For the last few weeks, they've trained almost night and day with little sleep - learning to be U.S. soldiers, not foreign terrorists.

Best Trained, But Not in the Best Way

Sgt. Christopher Campbell has been watching Geronimoes fight other Geronimoes and is impressed. "These guys in a month have transformed a lot. It's amazing how they picked up from one side and went to the other."

The Geronimoes are one of the best-trained units in the military, but they were focused primarily on being the best antagonists. That meant working independently with few restrictions. Now they must learn to act as a centralized unit dependent on one another for survival.

In their training to go to Iraq, they practice everything from interacting with local leaders to dealing with civilian complaints to planning covert missions to weed out insurgents.

Sgt. Jason Buda says it's different being on the other side.

"Because you have certain rules to follow. You have to basically interact with the people to try to do your combat mission as well as a humanitarian mission. The enemy doesn't have rules to follow."

Pvt. James Jennings used to launch rockets at the visiting soldiers. Now as he heads to Iraq, he believes he's more prepared than most. "We're a lot more aggressive. We used to go in chasing after people, getting it done real quick, so we move a lot quicker normally than we would before."

Advice from the Experienced

The fighting on the real streets of Iraq often has turned deadly. Since the invasion, more than 800 troops have died. The Army has tried to learn from real combat so they can better prepare soldiers for the dangers they face.

They bring in soldiers who just got back from Iraq to share those lessons learned. "Maybe if our words can help them stay alive over there, that's all we're aiming to do," says Sgt. Michael Ketchen.

He says the biggest problem was not understanding the language and cultural differences in Iraq. "Just like how to tell a person to stop over there. It's little things like that that are going to help you get by day to day."

The Army's trainers incorporate those lessons. They know good interaction with civilians is key to a successful operation. So in a simulated invasion of an Iraqi town to look for Iraqi insurgents, the American soldiers play a script on loudspeakers that says: "We are here in town to make it a safer place. We are here for your security. We need you to obey our orders."

After the exercise, they get a review of how they did. The new commander of Bravo company, Capt. Roy Tisdale, wants more from his soldiers. He says they've become so good at playing the enemy that they must now learn that not everyone is their adversary. "Now we're dealing with it and learning to deal with people who are not necessarily the bad guy - that are just upset or have an issue, you know, what is a real threat and what is a non-lethal threat, and handling each."

Emotional Occasions

The soldiers will be gone at least a year and no one feels that harder than their families. Tisdale's wife Kim is the volunteer leader of the family readiness group. She remembers getting the bad news in a double surprise: "He came home and he said two companies had been alerted, Alpha and Bravo. And I said, Well, good, you're not going to go. And he said, Well, Bravo company commander broke his leg that same day, so he's going to take over Bravo and go. So it was a big shock."

None of the families have had much time to prepare - the orders came so fast. The surprise deployment has meant an early marriage for Erin and Issac Barnhart who were high school sweethearts. Erin says: "It makes me real emotional to think about the possibility of him dying, and the intense stuff that they do every single day. They're out there in direct contact, and it's really hard to understand the fact that he could be gone. I mean, I've only had a very short amount of time to be with him. But I'm very proud."

Adding to a Storied Past

The deployment of the 509th begins a new chapter in the battalion's long storied history. The unit played a prominent role in some of World War II's key campaigns. On Nov. 8, 1942, the 509th spearheaded the Allied invasion of North Africa, jumping into Algeria after a 1,600-mile flight from England.

One of the veteran 509ers, John Devanie, went back to Fort Polk to see the deployment of the two units. He gathered the men around them and told them, "I feel like I'm seven feet tall being in front of you. Because I was the same age about 61 years ago. And I'm real thrilled to be here."

Two of the four companies will be left behind to continue training other soldiers. National Guardsmen will be sent to Fort Polk to fill in for the deployed soldiers. Splitting up the unit is difficult. Commander Griffith says: "None of them are my sons, none of them are my brothers, but they're my soldiers and there's a bond there that's tighter than anything I can imagine."

Griffith says his men are ready and believes their experience playing the bad guys for so long will serve them well now that they're the good guys.

See earlier stories:

U.S. Training Units May Have Go To Iraq

Troop Supply Getting Thin