Joan Cusack and her little brother, John, have co-starred in ten films together since the early 1980s; this week they join forces again to skewer the military industrial complex, the corporatization of America, and the teenybopper-pimping machine that is pop culture.

Cusack has made a career out of cinematic larceny, long stealing scenes in films like Working Girl, In & Out, and Grosse Point Blank, in which she played secretary to brother John's high school reunion-attending hit man. That delicious Girl Friday crackle is back in War, Inc., which sees Joan assisting John's hot sauce-swilling undercover assassin as Marsha Dillon, a ruthless agent forced to hide behind the guise of a Type-A corporate event coordinator.

We spoke with the Oscar-nominated actress about her Tomatometer, the psychology of George W. Bush, and the personal little film that may or may not be a sequel to Grosse Point Blank.

So I'm with Rotten Tomatoes...

Joan Cusack: Yes! What's my percentage?

Well, your overall Tomatometer is at 53%...

JC: Ooooh.

However, Toy Story 2 -- in which you star -- is our best-rated movie of all time on Rotten Tomatoes (it's currently at 100 percent).

JC: Wowww...So I've got that going for me! Well that's pretty good.

Of the reviews that have come in for War, Inc., one of the recurring comments is that you give the funniest performance in the whole movie.

JC: Aww, well that's nice. Well, I tried! We need comedies in the world! We need to laugh, it's all so hard.

Tamerlane agents Hauser (John Cusack) and Marsha Dillon (Joan Cusack) front the Brand USA trade show in "Turaqistan"

Did you know at the time, while you were filming, that you'd be the funniest thing in War, Inc.?

JC: Well I don't know if I am the funniest thing in War, Inc. But I know that I trust John -- is it implicitly, or complicitly? Implodingly? Impetusly?

Impotently?

JC: No! That's too weird...but I know it's so, so, so incredibly difficult to get a movie made, especially a political satire in the time we're in. So I just went and was like, "Whatever you want me to do, I'm ready to go!" Which is actually really fun because you get to just totally relax and trust someone, and not worry about anything. So I didn't really worry about my performance at all; I just went and had fun. It was fun; you know, at this point in my life it's like, I want to do stuff that's meaningful. So it was meaningful to support him. And it's fun to be around interesting people. And he's always around interesting people.

John not only stars in War, Inc., he also co-wrote and produced it. Did he bring you in very early on?

JC: We have a relationship, so I knew about the movie outside of just working on a movie. I knew about his passion for it; he's incredibly passionate about, and grateful to be able to make movies and do things that he loves and feels deeply about. And he's just a total movie junkie; he loves movies. So Dr. Strangelove and all the movies that we talk about and love and think are fun are just part of our life. I knew about this movie for a long time.

Did you have any hand in shaping your character, Marsha Dillon?

JC: Well I tend to come from a more psychological [angle] -- that's sort of my passion. I mean, I'm interested in the psychology of politics as well -- and obviously I'm interested in what's going on in the world -- but my passion is more the psychology of people. I did bring up the idea of George W. Bush wanting to please his father. [In War, Inc., Cusack's Marsha Dillon gives away a book "written" by Dubya about relating to his father, George Bush, Sr.] That could be a reason why he may have gone to Iraq, too; he wasn't the chosen son -- Jeb was the chosen son -- he was the drunk son. So the psychology of George Bush going to Iraq was interesting to me. I did add that piece.

One of your funniest scenes is one that is shot on a camera phone, where you're kind of freaking out at John.

JC: I was not sure; I thought that was too crazy. John was like, "It's so funny, Joan. It's so funny!" I was like, "Are you sure?"

Did you guys have any trepidation about the material, knowing how hard a sell political satires are, especially now? Any hesitation going as over the top as you guys went?

JC: I think that everything's hard now anyways, so you might as well do stuff that you love and believe in...so, no. Because it's all hard.

It does seem that the over-the-topness may be one of the obstacles that audiences will have to overcome, to let themselves go completely into the movie, to go with it -- and it's going so far...

JC: Right. Maybe a little cocktail before? Relax, and just let everything else drop away, and enjoy. Enjoy the journey. It's like a little punk rock, fast and furious, spirited journey.

Next: Shooting under budget constraints in Bulgaria; War, Inc. as Grosse Point Blank 2