Trump says Canada considering his offer to join US for Golden Dome missile defense

President Donald Trump said Tuesday that Canada was considering his offer to be part of his planned Golden Dome missile defense project.

Trump said if Canada remains a standalone nation, it will have to come up with $61 billion to get protection from a space-based missile defense system that the U.S. military has yet to build.

"I told Canada, which very much wants to be part of our fabulous Golden Dome System, that it will cost $61 Billion Dollars if they remain a separate, but unequal, Nation, but will cost ZERO DOLLARS if they become our cherished 51st State. They are considering the offer!," the president wrote in a social media post.

Trump has repeatedly said he wants Canada to become the 51st state of the U.S. Canadian leaders have been less than receptive to the idea so far.

Trump's comments came after King Charles III visited Canada on Tuesday to open the nation's parliament. The king vowed to "protect Canadians and their sovereign rights," but didn't mention Trump.

Trump wants to build a $175 billion missile defense shield that would protect the U.S. and Canada using multiple layers of defense against diverse potential attacks, making it much more complex than previous missile defense proposals. The Golden Dome would also include space-based sensors and interceptors, which the president said would be able to intercept missiles "even if they are launched from other sides of the world and even if they are launched from space."

The president said the missile defense system would be operational before he leaves office in 2029. Trump's plan is loosely modeled after Israel's Iron Dome – but on a much larger scale. Israel's Iron Dome defends a nation the size of New Jersey against short-range missiles built in underground tunnels. Trump's system would protect a much larger area – North America – against more challenging threats, including intercontinental ballistic missiles and hypersonic weapons.

Experts have said Trump's cost estimates and time schedule are optimistic. The project faces complex challenges and political risks, as The Center Square reported.