Woody Harrelson began our interview by climbing barefoot onto the interior windowsill of his hotel room overlooking New York's Union Square to point out an apartment across the square where he lived briefly, 15 or 20 years ago. (It's in the building that houses the Heartland Brewery, if you know the neighborhood. On the second or third floor, he couldn't remember.) Then he got into bed.

There wasn't an ounce of pretense about any of this, I swear. He was curious to get a look at that old apartment, and felt like telling me about it. He was tired, so he got into bed. When you meet Harrelson, you get a momentary glimpse of what a strange and exhausting job it must be to be famous. The job involves meeting an endless ocean of people you don't know and most likely will never see again. The obvious solution would be to retreat behind a well-rehearsed performance of your persona, to recycle a handful of gestures and mannerisms.

Harrelson, on the other hand, seems like a guy totally determined not to let the artificiality of these interactions impinge on his sense of who he is. Perversely, the fact that he is frank and thoughtful, and known to hold unorthodox political opinions he doesn't keep to himself, has only augmented his fame. You can't throw an empty Chardonnay bottle out your car window in west L.A. without hitting a Hollywood liberal, but Harrelson is something much rarer: a vegan, raw-foodist, antiwar, anti-capitalist, pro-marijuana, eco-funky, genuine radical who happens to be a beloved character actor with a good-ol'-boy demeanor.

Like the other journalists who showed up to talk to him about his role in "The Messenger," writer-director Oren Moverman's film about the United States Army's Combat Notification Unit (i.e., the dreaded door-knockers who show up with really bad news), I was asked by the publicists to restrict my questions to the film and Harrelson's acting career. It's a laughable request anyway, but in fact I would have needed to tie Harrelson up and gag him if I didn't want to hear his opinions about the wars in Iraq and Afghanistan, the dangers of capitalism and the looming possibility that Barack Obama could become a second LBJ.

For the first half of this decade, Harrelson was mostly absent from the movie screen; he did some theater and TV, a fair amount of environmental and pro-cannabis activism -- his illegal banner-drop from the Golden Gate Bridge goes back to 1996 -- and a lot of time with his family. (He lives most of the year on Maui with his wife and three daughters.) It seemed entirely plausible that the one-time "Cheers" star and Oscar nominee (for "The People vs. Larry Flynt") had burned up his 15 minutes, and then some.

It doesn't look that way now. Harrelson has appeared in more than two dozen films over the past three years, with more in the pipeline, and three of them are piling up on top of each other this fall. He co-stars in the action-comedy "Zombieland" and the apocalypse-thriller "2012," both of them likely to gross more in a single weekend than "The Messenger" will in its entire history. But Moverman's low-budget, high-intensity drama about the social and psychological costs of war is clearly "a labor of love" for all concerned, as Harrelson puts it.

In "The Messenger," Harrelson plays Capt. Tony Stone, a damaged, middle-aged hardass assigned to mentor the younger Sgt. Will Montgomery (Ben Foster), a decorated and wounded Iraq vet, as they take on the uniquely difficult task of informing civilians that their loved ones serving overseas won't be coming home. If that sounds wrenching, well, it is. But the acting is superlative -- Harrelson's right when he says that Foster's starring role has echoes of James Dean or the young De Niro -- and the half-improvised quality of the filmmaking feels dangerous and intimate but never showoffy.

When Stone and Montgomery are assigned to notify an NOK -- that's "next of kin," in Army parlance -- Foster and Harrelson literally went into the scene not knowing what would happen. They hadn't even met the actors playing the bereaved-civilian roles, and weren't sure whether they would break down in tears or respond with physical violence. (Moverman and co-writer Alessandro Camon partly based his screenplay on stories they heard from casualty-notification soldiers.) The story of what Stone and Montgomery have to do, and how it affects them, offers an intimate, human-scale portrait of the real costs of warfare.

Once Harrelson was safely tucked under the covers, wearing an Army T-shirt and a pair of blue jeans, I put my tape recorder on top of the duvet and we got talking. It was a nice big bed, and looked extra-comfy. Woody probably wouldn't have taken it the wrong way. I can't say I wasn't tempted.

This movie isn't connected to the Fort Hood shooting in any way, but still. It's kind of intense to be talking about this subject, about death and the military, right after that.

It's related in the sense that it's another sad story connected to this war. There's a lot of those, and that one's pretty devastating. I feel really terrible for those families.

And then I just happened to notice, on the same page of today's New York Times as that story, two more of those names in bold-face type. Two more soldiers whose families are going to be getting visits from guys like the one you play in the movie. [Just to put names to them, they were Spc. Tony Carrasco Jr., of Berino, N.M., and Staff Sgt. Amy C. Tirador of Albany, N.Y.]

It really is a devastating thing. I've had an evolution of sorts in terms of my attitude toward the war. Not in the sense of the war itself, which I do continue to think is wrong -- and I think it's pretty obvious what the war is about, both of them. During the course of making this, I had the opportunity to spend time with a bunch of soldiers and hear a bunch of stories, and you know, just start to feel a great deal of empathy and compassion toward the men and women who are over there working their asses off every day, not getting paid much and just putting their lives on the line for love of country. I do think that a big part of supporting the troops would be the concept of not sending them into battle in a war for resources.

So you think both Iraq and Afghanistan are wars over resources?

Iraq's about the oil and Afghanistan's about a pipeline. It always has been. They started building a pipeline as soon as there was a moment to do so. They started building a pipeline to the Caspian Sea, that's always been their directive. The guys from Chevron went in and met with the Taliban and realized those guys just weren't in control enough. That's why they wanted to oust them. Otherwise it's an absurd concept: You're going to war because a guy from some other country, a Saudi, is living somewhere in the mountains? So we're going to bomb Kabul, bomb the cities? That's absurd. It's a foreign policy gone way wrong. But that's how it always is. American foreign policy has always been, not about spreading democracy, but about spreading capitalism.

It does feel sometimes like our government suffers from some kind of amnesia or OCD. It's like they keep making the same foreign policy mistakes and just hoping it won't turn out quite as badly the next time.

I'm hoping that other countries look at us and say, "OK, there's the government and then there's the people." Granted, you'd like the will of the government to be conjoined with the will of the people. But it's the same way I've made the evolutionary step of looking at the war as separate from the soldiers. When I look at Russia, I don't look at Putin as representing the Russian people. I'm sure they'd love to get him out of there. Regardless, the Bushes and their various oligarchies have gotten us into a situation that's just very unfortunate.

At least at this point, it appears that Obama is pushing onward with the war in Afghanistan. Is he just constrained by geopolitics? Is he simply not free to say, "Look, we're not going to do this anymore"?

I think there's a lot of persuasive and powerful people around Obama. For a president to make his own decisions, I think that's a rarity. Even someone who we think of as our guy -- this is a guy with integrity, a guy who cares, for the first time in a long time -- in the Oval Office, even with him we don't really know who's pulling the strings. I think of every president as being a marionette. Whether he's any different, I don't know. Certainly his military advisors all want him to prosecute this war to the end, just as they did in Vietnam with LBJ.

It's just too depressing, I think we're going to have to hit the streets. Obama has the chance of becoming JFK or LBJ. I think JFK was one of our last great presidents, although I thought Carter was pretty great too. LBJ could have been a great president if he hadn't gotten bogged down in war, but that was quite a war to get bogged down in. Notwithstanding the fact that the war was wrong and they were talking about the Red Scare and the domino effect, if you go and read the Pentagon Papers they were also talking about rubber, tin and oil. They killed 2 and a half million people. What was it all for? In Korea they killed 4 and a half million. Like, we're liberating these people?

Well, one of the things this movie engages, in a way, is the fact that the combined U.S. fatalities in Iraq and Afghanistan are still below 4,500. Not that that's not terrible for those families, but it's not a number that has affected every town and every neighborhood, the way other wars did.

Yeah, but it's got to be more than 10 times that in terms of people with injuries, people strongly affected by it. I'm not sure what's going to make people hit the street, and, you know, I'm one of those people who's not on the street. I recognize that I'm just a guy bitching about it, not a guy who's doing anything.

The thing I love about this movie is that it really takes into account the consequences of going to war. It's been gratifying to me to hear from people who say, "Before it was just a thing in the news, a statistic." You're not really seeing a blown-up body, or seeing the coffins at Dover. I think it's a good thing that it puts a human face on it.

On one level I really dreaded those scenes where you and Ben went to knock on people's doors, do the notifications. They were hard to sit through. But on the other hand, I kind of needed that emotional catharsis. And they're very intense. In the first scene we see, the woman completely goes nuts and attacks you.

That was cool because of the way Oren shot it. We really didn't know what was going to happen. I didn't know she was going to hit me. You don't know what level the people are going to, the way they'll manage their grief. I think it made those scenes much more realistic. We never rehearsed, and never even met the people ahead of time. We shot those in one shot. All of that was really good.

They weren't all done in one shot, were they?

No, there's only two notification scenes that are actually one shot as you see them in the movie. One is Steve Buscemi's and then there's another one. But they were all shot as a one-camera, single-shot thing, with one camera following the action. Later on, if Oren did three takes or whatever, he'd join the different takes together, find whatever worked better. But they were designed to be one-shot takes, and it felt very real. It kept us right on our toes, and on edge.

That guy that you're playing felt very real to me. He's this hardass military lifer, an Army guy, and he's really messed up in ways he doesn't even recognize. I mean, this guy badly needs a hug.

[Laughter.] That's the best description yet. He badly needs a hug. That's true.

I thought there was terrific chemistry between you and Ben Foster, who plays your younger tag-team partner. Obviously you guys are pros so it can be hard to tell, but it felt like there was something real happening there.

Oh, it was incredible. I feel like he's my brother, I really love him. And as an actor, he's one of the best I've ever worked with, if not the best. Total immersion in the mind-set of the character, and constantly reminding himself of the significance of what we're doing. Just before a scene, maybe I'm not completely grounded, and he hands me these pictures of soldiers smiling or hanging with their kids, and they're marked with the dates they died, 2003, 2004, whatever. You can't help but be full of the emotion, with what this movie's connected to. It's one of the few times that I've felt emotional pretense really skirting on emotional reality. I don't think I said that right. It's just, you know, we're pretending, but the reality of it is big.

I've seen him in other movies, but people are really going to notice him this time, if they haven't already.

I think he's one of the most amazing actors. It's like I'm working with James Dean before people know that he's James Dean. I feel like I just did "East of Eden" with James Dean. His talent is so expansive, he's got a huge career ahead of him.

You took several years off, and for a while there it didn't seem clear whether you wanted to make Hollywood movies anymore. I guess you're at peace with them now! I'm not ranking on you for making movies. You're an actor. But does it help you somehow to do a smaller project like this one alongside a big movie like "2012," which can pay a lot of bills?

You know, I don't feel like a movie has to have a message, necessarily. If a movie's fun and funny and just great entertainment, that's enough. But it's nice to do a movie like "The Messenger" where you feel like people watch it and it's initiating conversations that are important. What more could you hope for?

I did take a long time off. I wasn't planning on taking that long, it just kind of happened. Five years. I did keep my hand in, in terms of doing some plays. I wasn't entirely out of the loop. But it was a good thing. I needed to spend some time with my kids. I needed to get away from it. I wasn't liking the whole, I guess you would say, business-y side of it. I came into acting initially because I loved theater, I wanted to be on Broadway. You know, I would have been on Broadway, but I ended up doing this show.

I've heard about that! Apparently you were on TV for a few years.

Yeah. Otherwise I just would have been here in New York. I love theater, that is where my passion is. There was a lot about "The Messenger" that felt very theatrical. Just really being in a scene with a fucking serious actor, like a young De Niro type of actor. It was just a great experience all the way around. I feel super lucky to be a part of this movie.

"The Messenger" opens Nov. 13 at the Angelika Film Center and Lincoln Plaza Cinemas in New York, with wider release to follow.