In a bizarre, meandering and lie-riddled speech at the Pentagon on Thursday morning, President Trump announced a new missile-defense strategy that includes additional weapons at sea, on the ground, in the air and in space.

Despite Trump's claims, nothing in the missile-defense strategy actually is new. And little if any of it will help to protect the United States from missile attack.

Following fawning introductions by Vice President Pence and Acting Defense Secretary Patrick Shanahan, Trump took the podium at the Pentagon.

“We’re talking defense and we're talking offense,” Trump said. “Our goal is simple. To ensure that we can detect and destroy any missile launched against the United States anywhere, any time and any place.”

To achieve that goal, the Defense Department will invest in a wide array of sensors, vehicles and munitions, Trump said.

“In the past, the United States lacked a comprehensive strategy for missile defense," Trump claimed. In fact, all the weapons in his new strategy has existed in some form for years or even decades. None originated in Trump's Pentagon. Few of them work very well.

According to an official summary of the missile-defense strategy, the Missile Defense Agency will request funding for 20 additional Ground-based Midcourse Defense rockets. At present, the Army operates 44 of the rockets at bases in Alaska and California.

The GMD is a 50-feet-tall rocket booster with a small “kill vehicle” at its tip. Cued by space-, land-, and sea-based radars in the seconds following the lift-off of an enemy rocket, a GMD climbs just outside of the atmosphere and releases its kill vehicle, which—in concept—strikes and destroys the incoming enemy rocket.

The Pentagon has poured more than $40 billion into the GMD system since the late 1990s. GMD rockets have missed their targets in nearly half of the system's tests, but the Pentagon hailed the most recent test, in May, as a major success.

In a scenario meant to represent a North Korean ICBM attack on the United States, a GMD rocket struck the target missile high over the Pacific Ocean. “The intercept of a complex, threat-representative ICBM target is an incredible accomplishment,” Vice Adm. Jim Syring, director of the Missile Defense Agency, said in a statement.

But Laura Grego, a missile expert with the Union of Concerned Scientists based in Massachusetts, examined the distances the two test rockets were expected to travel—and how quickly—and concluded that the target rocket probably would be significantly slower than an ICBM launched from North Korea would be.

A North Korean ICBM targeting Los Angeles would likely reach a velocity of 6.7 kilometers per second, Grego found. The target in the May test probably maxed out at 5.9 kilometers per second, if not slower, according to her calculations.

The GMD has never passed a truly realistic test. But that’s not stopping Trump from spending more on the system.

Trump's missile-defense strategy also calls for the military to develop a "scalable, efficient, and compact high-energy laser" and fit it to a drone that can fly near enemy territory and zap missiles right after they launch, or what physicists calls the "boost phase."

But the Pentagon has tried this sort of thing before. The administrations of presidents Bill Clinton George W. Bush and Obama together spent $5 billion developing a laser-armed 747 for boost-phase missile defense. The laser-armed 747 flew for the last time in 2012 after missing its targets in successive tests.

Even if it had worked, the whole concept of boost-phase missile-defense is problematic, as it requires U.S. forces essentially to wait overhead of potential missile launch sites. "There's nobody in uniform that I know who believes that this is a workable concept," then-defense secretary Robert Gates said in 2009.

Even sending in stealthy F-35 fighters for boost-phase intercepts, as one Republican congressman proposed, probably wouldn't work. "This sets such a short timescale for detection and interception you’d have to be very close to the launch site," Grego explained.

"Cray cray" is how Jeffrey Lewis, a nuclear expert at the Middlebury Institute of International Studies in California, described the F-35 plan. It's far from clear that using a drone for boost-phase intercepts, rather than a stealth fighter or a 747, solves the proximity problem.

Perhaps conscious of the airborne laser's conceptual flaws as a missile-defense system, the authors of Trump's missile-defense strategy dusted off an even older idea. Putting the laser in space.

"The space-basing of interceptors... may provide significant advantages, particularly for boost-phase defense," the official summary of the strategy asserts. "The Pentagon "will identify the most promising technologies, and estimated schedule, cost and personnel requirements for a possible space-based defensive layer."

But space-based interception is one of the oldest, and most flawed, missile-defense schemes of all. The Pentagon first began developing ICBM-destroying space weapons in the 1980s. The concept has fallen in and out of favor over a period of more than 30 years without ever resulting in a working weapon.

The main reason is simple: Scale.

While the military and the defense industry possess the know-how to build a missile-or laser-armed satellite, the sheer number of satellites that a reliable space-based missile shield would require makes it impractical.

A satellite in low orbit is constantly moving relative to Earth. "This means an interceptor that is within range of a missile launch site at one moment will quickly move out of range," David Wright, a physicist with the Massachusetts-based Union of Concerned Scientists, explained in a series of blog posts.

Round-the-clock coverage of all the potential launch sites in North Korea alone could require hundreds, possibly thousands, of armed satellites, Wright estimated. A 2012 study by the National Academies of Science and Engineering projected that such as system would cost at least $300 billion, or roughly half of the military's entire annual budget.

At present, the United States possesses around 860 satellites. Building an orbital missile shield could easily double that number. Launching and controlling all of those extra satellites would stretch U.S. space infrastructure to the limit. "It is a hugely difficult thing to do," Samson warned.

Chock full of stale ideas that never have worked, the Pentagon's new missile-defense strategy is the Pentagon's old missile-defense strategy. Unworkable and unaffordable.

Trump either doesn’t realize that or doesn’t care. “I’m committed to a missile-defense program that can shield ever city in the United States,” Trump said in his Pentagon speech.

It’s an empty promise.