A silo housing a ground-based interceptor missile is covered at the Ft. Greely missile-defense complex in Fort Greely, Alaska.Mark Meyer / Reuters

“We have some very bad players out there,” President Donald Trump warned from a Pentagon podium on Thursday. Advanced missile technologies are spreading among great powers and rogue actors alike, and with them new threats to the United States. So Trump threatened back. “We’re a good player, but we can be far worse than anybody, if need be.”

The blueprint he unveiled for doing that, the Pentagon’s long-delayed Missile Defense Review, outlined all kinds of potential high-tech systems to detect and shoot down threatening projectiles, including from outer space. Though Trump didn’t mention them by name, it was a message clearly aimed at rivals like Russia and China, which have made a public show of their advances in new weapons like ultrafast missiles. And it also singled out North Korea as a still-potent threat—even as a high-level North Korean official was in Washington, D.C., to plan another summit between Donald Trump and Kim Jong Un.

But there’s a problem: The strategy relies mostly on tech and hardware solutions that are either unreliable or experimental verging on speculative. It gives no indication of how much any of its recommendations will cost, or where the money will come from. Still, it was a signal of how the military is trying to reorient itself from nearly two decades of the War on Terror—and back toward great-power competition.

Briefing reporters on Thursday, John Rood, the undersecretary of defense for policy, declared that the document marks a “new era in missile defense.” So far, that largely amounts to a list of systems to be tested and studied, with little in terms of new technology actually deployed. “I don’t see anything in here that fundamentally alters any balance of power,” says John Plumb, who previously served as the principal director for nuclear and missile-defense policy at the Pentagon.

The document notably omitted a discussion of funding, and Pentagon officials repeatedly declined to answer questions about how much all of this would cost. “There’s not enough money to throw at it to do all of these things,” says Plumb, now a senior engineer at the RAND Corporation.

There are also departures from the Obama administration’s strategy, and a major one is the focus on space.

Right now, if a missile were hurtling across the sky toward the U.S. from, say, North Korea, stopping it would involve shooting it out from the ground with another missile. There are 44 interceptors buried in Alaska and California for this purpose—with the North Koreans in mind—and more being added. They work like a bullet hitting a bullet, and as such they’re not especially reliable: The former Missile Defense Agency director Trey Obering once said that their odds of success were about as good as a coin toss, and they’ve shown uneven improvement.

But when it comes to the newer, faster kinds of weapons Russia and China are developing, there is, so far, not much that could stop them even some of the time. As a first step, the Pentagon wants to expand its ability to monitor missiles from space by putting more satellite sensors in the sky.

That still leaves the problem of actually hitting the missile. The idea of putting armed satellites in space to do so, which the new strategy promises to study, is controversial and expensive. “It’s not a very popular idea,” says Plumb. Some arms-control advocates, scientists, and others have warned about the implications of putting weapons in orbit ever since the Reagan administration first proposed studying the use of space lasers in missile defense back in the 1980s. (The Strategic Defense Initiative, Reagan’s missile-defense research initiative, got the derisive nickname “Star Wars” for proposals much like some of those unveiled on Thursday.)

What all this adds up to is an effort to solve a political problem with expensive hardware. For years, defense officials have worried about the rise of China and Russia, even as policy has tended to focus on challengers like Iran, North Korea, and terrorist groups. In the meantime, China and Russia have been developing new ways to confront the United States. On Thursday Trump vowed to stay ahead of America’s enemies—but the country is in some ways only just catching up.

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