President Donald Trump has laid out new details of his ambitious plan for a multibillion-dollar ?Golden Dome? missile defense system to protect the United States from foreign attacks, saying it should be complete before he leaves office.

?We?ll have it done in three years,? Trump told reporters as he detailed the plan in the Oval Office on Tuesday. ?Once fully constructed, the Golden Dome will be capable of intercepting missiles even if they are launched from other sides of the world.?

High-profile defense contractors and tech companies - including Elon Musk?s SpaceX - are already jockeying for the job to build the shield, making pitches directly to Defense Secretary Pete Hegseth. But experts have also voiced skepticism about the timeframe and cost put forth by the White House ? or even the feasibility of such a project.

The US administration has remained vague on its plans for developing the missile shield, which takes inspiration from Israel?s Iron Dome.

While it is not yet clear what exactly the so-called Golden Dome will look like, there are significant differences in scope and scale to Israel?s shield. The Iron Dome selectively protects populated areas from short-range threats in a country the size of New Jersey; Trump wants a space-based missile defense system capable of defending a country around 450 times larger, from advanced ballistic and hypersonic missiles.

The project will cost about $175 billion, Trump said, and will be led by Gen. Michael A. Guetlein, vice chief of space operations at the United States Space Force. Trump said $25 billion dollars will be allocated from his sweeping spending cut and tax bill, which he?s pushing House Republicans to pass.

He also said ?Canada has called us? wanting to be involved in the project and to be protected under the Golden Dome. In a statement provided to Reuters, the office of Canadian Prime Minister Mark Carney said that he and his ministers, along with their American counterparts, were discussing how to negotiate a new security and economic relationship between the two countries ? which ?naturally include strengthening NORAD and related initiatives such as the Golden Dome.?

Earlier in May, the Pentagon submitted small, medium and large options to the White House for developing the Golden Dome. Trump didn?t specify a final choice on Tuesday but said that they had ?selected an architecture for this state-of-the-art system.?

The administration?s cost and construction time estimates run contrary to those given by other military officials. Retired Rear Adm. Mark Montgomery previously told CNN he believes creating a ballistic missile defense system may be possible in 7 to 10 years, but even then, it will have severe limitations, potentially capable of protecting only critical federal buildings and major cities.

Other experts have told CNN that several hundreds of billions of dollars would probably be a conservative estimate, with some saying projecting the total cost of such a project was essentially impossible.

The US has talked about building a missile shield for decades, but it has never been realized because of gaps in technology and cost.

The Defense Intelligence Agency recently released an unclassified assessment underscoring how US adversaries like China, Russia, Iran and North Korea could potentially target the American mainland with a variety of ballistic missiles, long-range cruise missiles, bombers and hypersonic missiles.

Chinese officials reacted to Trump?s announcement Tuesday by condemning the Golden Dome and urging the US to abandon their plans. The project ?carries a strong offensive nature? and could heighten ?space militarization? and an arms race, undermining global security, said Mao Ning, spokesperson for China?s Ministry of Foreign Affairs.

Constructing the shield is a massively complex task that will require a network of government agencies and private contractors, according to multiple sources familiar with the planning process. (CNN)

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