What caused the arm race between the US and USSR?

The arms race between the US and the USSR was primarily driven by ideological differences, as both superpowers sought to assert their political and military dominance during the Cold War. The fear of nuclear war and the desire for national security motivated each side to develop and stockpile increasingly sophisticated weapons. Additionally, espionage and technological competition fueled the race, as each nation aimed to outpace the other in military capabilities. This escalation was characterized by the development of nuclear arsenals, intercontinental ballistic missiles, and various strategic defense systems.