alt Hacker NewsFirst off, I think this is all conspiratorial nonsense. But as for Golden Dome - it's more about offense than defense. The reason MAD works is because if you destroy another country then they also destroy you. But if you can negate the latter part, then you're simply left with 'you can destroy another country.' In other words if you can negate an enemy's ability to retaliate, then you can nuke or invade whoever you want, without concern about retaliation.
The geographic location of the US would make this basically a godmode type 'weapon' because a conventional invasion of the US is practically impossible since you'd need to bring mass number of forces across an ocean and those ships would simply get popped. Even coming through South America wouldn't really work because the Isthmus of Panama could just be hyper-fortified. And even then you still have to get to South America! But the US' chosen enemies are somehow half-way around the world, and we have plenty of proxy armies we can throw against them. And when our victims retaliate against our proxies then we'll support them with a powerful army of flags, emojis, and slogans on social media.
All that said, this still doesn't work. Nuclear fallout would affect the globe, with a Russia-US conflict estimated at driving some 5 billion deaths from climatic effects alone. [1] Missile defense will likely always lag behind offense simply because offense is akin to shooting a bullet at a giant stationary target, whereas defense is akin to shooting a bullet at a bullet. It requires a massive technology disparity to be effective. And there are also other forms of nuclear strikes than missiles - such as nuclear created radioactive (and super sized) tsunamis. And if a country really wants the flashing red button, then a salted nuke could likely kill off most of all of humanity (and everything else on Earth), let alone any given country.