The New Strategic Arms Reduction Treaty (START) was signed by presidents Barack Obama and Dmitry Medvedev in Prague on April 8, 2010, and went into effect in February 2011. It superceded START I and the Strategic Offensive Reductions Treaty (Moscow Treaty).
Excerpt from blog post announcing new treaty:
THE NEW START TREATY AT A GLANCE
Treaty Structure: The New START Treaty is organized in three tiers of increasing level of detail. The first tier is the Treaty text itself. The second tier consists of a Protocol to the Treaty, which contains additional rights and obligations associated with Treaty provisions. The basic rights and obligations are contained in these two documents. The third tier consists of Technical Annexes to the Protocol. All three tiers will be legally binding, and all three tiers will be submitted to the U.S. Senate for its advice and consent to ratification.
Strategic Offensive Reductions: Under the Treaty, the U.S. and Russia will be limited to significantly fewer strategic arms within seven years from the date the Treaty enters into force. Each Party has the flexibility to determine for itself the structure of its strategic forces within the aggregate limits of the Treaty. These limits are based on a rigorous analysis conducted by Department of Defense planners in support of the 2010 Nuclear Posture Review.
- 1,550 warheads. Warheads on deployed ICBMs and deployed SLBMs count toward this limit and each deployed heavy bomber equipped for nuclear armaments counts as one warhead toward this limit. This limit is 74% lower than the limit of the 1991 START Treaty and 30% lower than the deployed strategic warhead limit of the 2002 Moscow Treaty.
- A combined limit of 800 deployed and non-deployed ICBM launchers, SLBM launchers, and heavy bombers equipped for nuclear armaments.
- A separate limit of 700 deployed ICBMs, deployed SLBMs, and deployed heavy bombers equipped for nuclear armaments. This limit is less than half the corresponding strategic nuclear delivery vehicle limit of the START Treaty.
Verification and Transparency: The Treaty has a verification regime that combines the appropriate elements of the 1991 START Treaty with new elements tailored to the limitations of the Treaty. Measures under the Treaty include on-site inspections and exhibitions, data exchanges and notifications related to strategic offensive arms and facilities covered by the Treaty, and provisions to facilitate the use of national technical means for treaty monitoring. To increase confidence and transparency, the Treaty also provides for the exchange of telemetry.
Treaty Terms: The Treaty's duration will be ten years, unless superseded by a subsequent agreement. The Parties may agree to extend the Treaty for a period of no more than five years. The Treaty includes a withdrawal clause that is standard in arms control agreements. The 2002 Moscow Treaty terminates upon entry into force of the New START Treaty. The U.S. Senate and the Russian legislature must approve the Treaty before it can enter into force.
No Constraints on Missile Defense and Conventional Strike: The Treaty does not contain any constraints on testing, development or deployment of current or planned U.S. missile defense programs or current or planned United States long-range conventional strike capabilities.