[The writers are, respectively, the U.S. secretary of state and secretary of defense.]

For decades, American inspectors have monitored Russian nuclear forces, putting into practice President Ronald Reagan's favorite maxim, "Trust, but verify." But since the old START Treaty expired last December, we have relied on trust alone. Until a new treaty comes into force, our inspectors will not have access to Russian missile silos and the world's two largest nuclear arsenals will lack the stability that comes with a rigorous inspection regime.

Before this session of Congress ends, we urge senators to approve an arms control treaty that would again allow U.S. inspectors access to Russian strategic sites and reduce the number of nuclear weapons held by both nations to a level not seen since the 1950s....