In testimony at their Senate confirmation hearings, Secretary of State Colin Powell and Secretary of Defense Donald Rumsfeld indicated that the new Bush administration would spend billions on what is already the most expensive research project in the history of the United States government -- an antimissile defense system.

President Ronald Reagan's "Strategic Defense Initiative," or "Star Wars," has cost the United States $60 billion since the mid-1980s. Congress most recently financed SDI in 1999, when, quietly and with bipartisan support, $6.6 billion was doled out for further development of national missile defense. Yet it hasn't always been clear where the money goes, what has been developed so far or whether any of these systems will ever work.

According to Powell, national missile defense, like the Internet, is essential to America's future. Rumsfeld, who was secretary of defense from 1975 to 1977 under President Ford, explained in his testimony that defense shields "work without being fired" because "they alter behavior." Both men also have declared the Anti-Ballistic Missile Treaty of 1972 to be virtually obsolete.

Frances FitzGerald, historian and Pulitzer Prize-winning author of "Fire in the Lake," offered an in-depth account of SDI under the Reagan administration with her acclaimed work "Way Out There in the Blue." Heralded for its clear and elegant style, FitzGerald's book unveils the daunting complexities surrounding missile defense, from its bizarre scientific origins to Reagan's thorny personal motivations to its role in the arms race.

Salon spoke with FitzGerald about what lies ahead for missile defense.

Now that the Republicans are in office, missile defense is a hot issue. But it seems as if "Star Wars" and all its progeny are still shrouded in mystery.

No one ever knew quite what it was. It was a bunch of research programs. Reagan promised it would protect us, like a roof over our heads. It always had to do with weapons in space.

How did it change with the Bush and Clinton administrations?

There have been many "sons of Star Wars." They're mostly just ideas too. The first Bush administration supported "Brilliant Pebbles," the notion that these things rattling around in space would intercept missiles.

Clinton, though, was developing a ground-based system. They built various sorts of prototypes. Missile defense isn't one thing -- it's radars and all kinds of stuff. It's not a scientific problem -- having it all work at once is the problem. And Clinton's system has various problems; two out of three tests have failed. A big issue is whether or not the system can deal with decoys.

What was the Clinton administration's rationale for it?

Rationales change all the time. The Clinton administration rationale was to protect us from "rogue states" -- which did not mean Russia or China. It meant Iraq, Iran and Korea. Then, they decided that they weren't "rogue states" and Madeleine Albright started talking about "states of concern."

But all of those countries have unique considerations.

The problem with China is that, essentially, it has ICBMs [Intercontinental Ballistic Missiles], but it only has 20 of them. We kept trying to reassure them that our system wasn't aimed at them. But if it actually worked, it might suppress their deterrent force. Therefore, if you build anything bigger, it might definitely affect them. So what choice do they have but to build up more ICBMs of their own?

With Russia it's another problem. They have something like 6,000 strategic warheads. They want to bring strategic warheads below 2,000, but they're not so keen on doing that if we're building up our defense.

What Putin has been pushing for -- "boost-phase" -- is the notion that you have short-range missile defense. You put it offshore or in a neighboring country; you put it on a ship near Iraq, for example. And you have the ability to shoot down ICBMs on the way up, as opposed to on the way down. The idea would be that nobody gets total, country-wide defense. Instead, you get defense from states that appear dangerous. So it wouldn't actually threaten the Russian deterrent system.

Can North Korea's missiles reach us?

No.

How do you think the new Bush administration will move on missile defense?

They have all saluted. You can't have a Republican administration these days that wouldn't be all for it. They may start to tell us that they are developing space weaponry, but that it will take a long time. The right really wants space. And the potential for attack as well. You can use a weapon either way ...

It could be that the administration will say that they're doing a terrific thing and that it's much better than what the Democrats did. They're just going to have to make a decision about what it is they actually want.

And Colin Powell?

You can't imagine that Colin Powell's foolish enough to think that this thing works, but he's been toeing the same general line ever since 1987. Powell supported the broad interpretation of the ABM Treaty in the first place. He saluted it then and he has saluted it now.

But the person to look at isn't Powell, it's Rumsfeld. Colin Powell will have to deal with the diplomatic fallout, but the operative is Rumsfeld. He's a very powerful secretary of defense.

His [Commission to Assess the Ballistic Missile Threat to the United States] reported in 1998, if I'm correct, that these small countries might be able to develop international-range ballistic missiles in a small-enough time frame. That got everybody upset. This was used by the Republicans to push [missile defense funding] through Congress.

How do you think the Democrats will act under the Bush administration?

Senator Carl Levin from Michigan, the [now former] chairman of the Senate Armed Services Committee, is serious about protecting the ABM Treaty. Senator Joseph Biden from Delaware is serious about it.

But it's a good question what the Democrats will do. They all signed onto it in 1998 when the impeachment trial was going on in the Senate. They were quiet about it then. But it won't be easy to take a stance in this administration.

Do you think they will fight it at all?

They may now that there's a Republican president. It's going to be difficult. [The Bush administration] hasn't told us what system they want. If they start developing something other than what was tested last year, it will take a long time.

Any sort of rational or logical missile defense strategy floating around out there?

Well, there are always two questions. First, can you develop it? Second, if you could, would it enhance our national security?

... Or would it threaten it even more?

Yes.

How do you feel about deterrence as a defense strategy in general?

It seems to me that deterrence has worked for a long time and I don't know why it shouldn't continue to work. Any country that attacked us would be a pile of ruins the next day.

We have total faith in it at the moment.

Why do people support this even though they know it hasn't worked and maybe never will?

It's a very political weapon.