Late last week, President Barack Obama and Russian President Dmitri Medvedev announced an agreement to reduce stockpiles of nuclear weapons. The new treaty expands upon the Strategic Arms Reduction Treaty (START) proposed by President Ronald Reagan in 1982 and finally signed by President George H. W. Bush in 1991. The new START reduces the number of deployed warheads from 2,200 to 1,550 and cuts the number of launchers in half. It will allow both sides to continue to monitor nuclear stockpiles with expansions to the already-intensive and proven system of verification set up in the original START treaty. As Reagan rightly said, âÄútrust but verify.âÄù Additionally, the treaty wonâÄôt constrain the United States in conventional weapons or missile defense resea rch. This treaty is a laudable step toward ObamaâÄôs vision of a nuclear-free world. It will significantly cut the number of missiles pointed at American cities, destroy nuclear materials and ultimately reduce the risk of mass annihilation âÄî intended or not. It also represents the slow deterioration of the regimes, systems and threats that defined the 20th century and the daily reality of studentsâÄô parentsâÄô generation. Arms control has a long history of bipartisanship. With ObamaâÄôs signature next week, the Senate should move to ratify it quickly. Leaders today have a moral obligation to solve such problems of the past before a new generation, unscarred by the nuclear terror of the Cold War, inherits them.