Editorial: Trump is fixating on another ‘wall’ that will almost certainly fail to live up to his promises

In 1983, in what came to be known as his “Star Wars” speech, President Ronald Reagan unveiled an ambitious vision for a missile defense system that would render the need for traditional nuclear deterrence unnecessary. Reagan asked: “What if free people could live secure in the knowledge that their security did not rest upon the threat of instant U.S. retaliation to deter a Soviet attack, that we could intercept and destroy strategic ballistic missiles before they reached our own soil or that of our allies?”

The “Star Wars” label proved prophetic, because Reagan’s vision of an impermeable shield that would deflect incoming nuclear missiles proved to be the stuff of science fiction. Missile defense has achieved modest successes, but it also has been marked by embarrassing failures. It has not rendered obsolete traditional nuclear deterrence theory — the notion that all-out war is avoidable only if both sides are convinced it will lead to their own destruction — nor has it obviated the need for arms-control negotiations.

Yet now President Trump is offering a similarly expansive vision of security through missile defense systems, including interceptors deployed in outer space. In a recent speech introducing the Defense Department’s latest Missile Defense Review, Trump announced “a new era in our missile defense program,” explaining that “our goal is simple: to ensure that we can detect and destroy any missile launched against the United States — anywhere, anytime, anyplace.”

That’s not a simple goal; experts doubt that it can be achieved no matter how much money is invested in the “advanced technology and research” Trump promised. Fortunately, the Pentagon’s Missile Defense Review is more realistic in its objectives than the president was in his speech. But there is a danger that his excessive confidence in the promise of missile defense will lead to wasteful expenditures by Congress and a continued failure by the administration to take arms-control negotiations seriously.

Missile defense systems can be effective against shorter-range missiles, as Israel has demonstrated with the Iron Dome system it has used to deflect rockets fired from the Gaza Strip. The United States also has had success in tests of systems aimed at shorter-range missiles. It’s not clear, however, that missile defense will ever be able to block most or all intercontinental ballistic missiles such as those possessed by Russia, China and probably North Korea.

For example, the United States currently maintains 44 long-range, ground-based interceptor rockets at Fort Greeley, Alaska, and Vandenberg Air Force Base in California, a number that the Pentagon plans to increase to 64. But test results have been discouraging, and most of the interceptors are believed to have faulty circuit boards that could cause them to go astray. Even if accuracy is improved, there is no guarantee that this or any other missile defense system would hermetically seal off the United States from incoming long-range missiles.

Even more dubious is Trump’s suggestion that outer space should be turned into “a new war-fighting domain” through the deployment of a space-based missile defense system that would somehow involve his much-ridiculed “Space Force.” In a critique of Trump’s speech, Kingston A. Reif of the Arms Control Assn. cited studies that he said demonstrated that space-based interceptors are “unaffordable, unworkable, and massively destabilizing.”

It’s somewhat reassuring that the actual Missile Defense Review published by the Pentagon is more modest in its discussion of space-based missile defense. It proposes a six-month study that will “identify the most promising technologies, and estimated schedule, cost, and personnel requirements for a possible space-based defensive layer that achieves an early operational capability.”

Enter the Fray: First takes on the news of the minute »

Technological issues aside, an overemphasis on missile defense can threaten U.S. security by reducing incentives for arms control negotiations while creating a fear among other nuclear powers that the U.S. might take advantage of a missile defense breakthrough to launch a first strike. It was precisely because defensive systems can be perceived as offensive that the U.S. and the former Soviet Union in 1972 signed the Anti-Ballistic Missile Treaty — an agreement from which the U.S. withdrew during the George W. Bush administration.

The Trump administration, citing Russian violations, has indicated that it will withdraw from another important arms-control treaty, the 1987 Intermediate-Range Nuclear Forces Treaty. An exaggerated confidence in missile defense might also tempt the administration to abandon the New START treaty with Russia, which limits offensive nuclear weapons and is set to expire in 2021 unless it is renewed.

Trump is susceptible to simplistic thinking; witness the magic qualities he attributes to his proposed wall on the Mexican border. As the Pentagon studies missile defense options, we hope it — and Congress — won’t be unduly influenced by the president’s similarly unsophisticated approach to a “wall” in space that would keep missiles out.

Follow the Opinion section on Twitter @latimesopinionand Facebook