Trump unveils plans for US missile defense shield that could cost billions

President Donald Trump unveiled at the White House Tuesday afternoon his plans to build a massive missile shield system to protect the United States against threats from North Korea and elsewhere. The project echoes President Ronald Reagan's failed "Star Wars" program, and experts say it could cost anywhere from tens of billions to hundreds of billions of dollars, depending upon how it's set up.

Three U.S. officials confirmed the plans ahead of the announcement. Trump was joined by Defense Secretary Pete Hegseth and Gen. Michael Guetlein, the Pentagon's vice chief of space operations. Guetlein is being asked to lead the "Golden Dome" project, one of the officials said.

"This design for the Golden Dome will integrate with our existing defense capabilities and should be fully operational before the end of my term," Trump said in announcing the plan. "So we'll have it done in about three years. Once fully constructed, the Golden Dome will be capable of intercepting missiles even if they are launched from other sides of the world and even if they are launched from space."

Trump began calling for a U.S. missile defense shield similar to Israel's Iron Dome after watching Israel deflect missiles and drones amid Iran's attacks in 2024. Military officials said at the time that they hadn't expressed a need for such a shield to defend the U.S., citing existing missile defense systems already in use. Meanwhile, critics scoffed at the idea of a country like the U.S., which isn't threatened by missiles from its neighbors, Canada and Mexico, and is buffered by two oceans, needing such a system.

But Trump's talk of building "the greatest dome of them all" was met with cheers from crowds at his rallies so much that Republicans included the construction of a U.S. missile shield in its party platform ahead of the 2024 elections. In January, Trump signed an executive order calling on Hegseth to make it happen.

"The threat of attack by ballistic, hypersonic, and cruise missiles, and other advanced aerial attacks, remains the most catastrophic threat facing the United States," Trump wrote in the Jan. 27 order.

Since then, "the Defense Department has gathered the brightest minds and best technical talent available to review a full range of options that considers current U.S. missile defense technology and cutting-edge innovation to rapidly develop and field a dependable umbrella of protection for our homeland," Sean Parnell, chief Pentagon spokesman and Hegseth's senior adviser, said earlier this week amid reports the Defense Department has been working on the proposal.

Still unclear is how big and comprehensive the system would be.

Among the questions is: Would Trump's "Golden Dome" be designed to protect every inch of U.S. territory, or would the focus be put on major cities? Depending on scale, the initiative could take years to develop and build, even with advances in technology such as remote sensing, image processing and uncrewed aerial systems, according to congressional researchers.

Also in question is whether such an ambitious program might siphon away money from other vital programs. The Air Force, for example, is in the process of replacing 400 of its intercontinental ballistic missiles built in the 1970s with new ones.

Earlier this month, the Congressional Budget Office estimated the U.S. may need to spend anywhere from $161 billion to $542 billion over 20 years to develop and launch a network of space-based interceptors.

According to the CBO, these estimates are lower than they would have been years ago because of a decline in the cost of launch services available. But the office noted increasingly sophisticated technology used by North Korea and the scope of Trump's stated goals as the reason the cost would remain high.

Israel developed its "Iron Dome" system to zap rockets and mortar fire out of the sky -- acting as a kind of shield over a country under the near-constant threat of short-range and medium-range missile attacks. The multibillion-dollar system played a major role in successfully defending Israel last April when Iran launched some 300 missiles and drones at the Jewish state in retaliation for an Israeli airstrike that killed a top Iranian commander.

The U.S. currently relies in part on the Ground-Based Midcourse Defense program, which is designed to knock down rogue long-range missiles from a country like North Korea. It would, however, have more limited utility if there were ever a large-scale attack from a country with a hefty arsenal like Russia.

Expanding that system to cover every inch of the U.S., though, would likely cost billions of dollars at a time when the country also is trying to protect against attacks in cyber and space. China and Russia are now pursing hypersonic weapons, while administration officials this spring acknowledged Russia's pursuit of nuclear capabilities in space, greatly complicating what it means for any one system to keep the U.S. safe.

Last year, Trump often noted that the U.S. had spent some $3 billion to help Israel manufacture and maintain its system.

"In my next term, we will build a great Iron Dome over our country, a dome like has never seen before, a state-of-the-art missile defense shield that will be entirely built in America," Trump said at a June rally in Wisconsin as the crowd applauded.

"We're going to build the greatest dome of them all," he promised.

ABC's Nathan Luna contributed to this report.