TCS President Steve Ellis and Policy Analyst Gabe Murphy break down President Trump's Golden Dome missile defense program—an ambitious vision to shield the entire United States from nuclear attack. With potential costs ranging from $3.6 to $6 trillion and fundamental technical challenges that make near-perfect interception virtually impossible, Golden Dome represents fiscal irresponsibility on a massive scale. Congress has already approved over $24 billion without even seeing a basic architecture for how the system would work. We examine why hitting hundreds of nuclear warheads traveling at 15,600 mph is far more complex than Israel's Iron Dome, how nuclear explosions could blind the system's own radars, and why pursuing this program could trigger a dangerous new arms race in space while undermining arms control efforts. Bottom line: if it doesn't work, don't fund it.