The nuclear triad is a military strategy that consists of three components, each of which is capable of delivering nuclear weapons: strategic bombers, intercontinental ballistic missiles (ICBMs), and submarine-launched ballistic missiles (SLBMs). The concept of the nuclear triad was developed during the Cold War to ensure that the United States had a secure and reliable second-strike capability, meaning that the US would be able to deliver a retaliatory nuclear strike even if its nuclear weapons were destroyed in a first strike.
In addition to serving as a deterrent, the nuclear triad has also been used for strategic signaling. By publicly displaying its nuclear forces, the US has been able to demonstrate its commitment to its allies and its willingness to defend them with nuclear weapons if necessary. Furthermore, the US has been able to use its nuclear forces to signal its resolve in areas of dispute, such as the Korean peninsula.
The nuclear triad is an important part of the US nuclear arsenal, and serves as a powerful deterrent to aggression. It is an effective way to ensure that the US is able to respond to any nuclear attack, and serves as an important tool for signaling US resolve and commitment to allies.