Why did Reagan want to develop the sdi program?

President Reagan sought to develop the Strategic Defense Initiative (SDI) program primarily to enhance U.S. national security by creating a protective shield against nuclear missile attacks, particularly from the Soviet Union. He believed that by advancing missile defense technology, the U.S. could deter potential aggressors and reduce the reliance on mutually assured destruction as a deterrent strategy. Reagan also aimed to shift the balance of power in favor of the U.S. and demonstrate a commitment to defending American citizens against nuclear threats. Ultimately, SDI was part of his broader strategy to end the Cold War by applying pressure on the Soviet Union.