Russia and China have escalated their opposition to the United States' missile defense initiatives, particularly the proposed 'Golden Dome' concept, which they argue could destabilize global nuclear deterrence. This criticism emerges as the New START treaty, the last significant nuclear arms control agreement between the U.S. and Russia, approaches its expiration in February 2026. The treaty has been crucial in limiting the number of strategic nuclear warheads and delivery systems, and its potential lapse raises concerns about increased mistrust and geopolitical tensions. Both nations assert that advanced U.S. missile defense systems could undermine the credibility of nuclear deterrence, prompting fears of a renewed arms race. Furthermore, Russia's ongoing military exercises in Belarus, involving tactical nuclear-capable systems, have intensified scrutiny from NATO and Western nations, highlighting the interconnectedness of missile defense modernization and tactical nuclear deployments. As the global nuclear framework faces uncertainty, experts warn that the absence of verification measures could exacerbate tensions and lead to an escalation in offensive capabilities among rival states.