Everyone wants equitable standards of security. John Holum, the senior advisor for arms control at the State Department, says the US has not forsaken deterrence. He rejects the notion that a US Missile defense system is a way to achieve global military dominance. I know this argument comes up, but I don't think it's a broad license for the United States to engage unilaterally. This is not an abandonment of deterrence.
Deterrence works in two ways.
You also want to convince them that the benefit of attacking is negligible. What this would do is persuade a country like North Korea that an attack on the United States would be both fatal and futile, so it would reinforce deterrence. That 1972 agreement, signed by Soviet President Leonid Brezhnev and US President Richard Nixon, prohibits nationwide missile defenses. The intent was to stop a spiraling offensive-defensive arms race. Putin's government has agreed to reduce its nuclear arms, but he says if the US deploys a national missile defense system, Russia will not shrink its nuclear arsenal.