JUDY WOODRUFF: President Obama and Russian President Medvedev finalized an agreement today to slash nuclear arsenals by a third. Mr. Obama called the pact a step towards a world without nuclear weapons.
U.S. PRESIDENT BARACK OBAMA: After a year of intense negotiations, the United States and Russia have agreed to the most comprehensive arms control agreement in nearly two decades.
JUDY WOODRUFF: The president sealed the landmark deal with a phone call to his Russian counterpart this morning.
BARACK OBAMA: We have turned words into action. We have made progress that is clear and concrete. And we have demonstrated the importance of American leadership and American partnership on behalf of our own security, and the world's.
JUDY WOODRUFF: Together, the United States and Russia possess more than 90 percent of the world's nuclear weapons. The U.S. has 2,100 deployed strategic warheads. Russia has 2,600.
BARACK OBAMA: The new START treaty makes progress in several areas. It cuts, by about a third, the nuclear weapons that the United States and Russia will deploy.
JUDY WOODRUFF: Today's deal replaces the 1991 Strategic Arms Reduction Treaty, or START, that expired in December. And it goes beyond the 2002 Moscow treaty signed by then Presidents George W. Bush and Vladimir Putin.
Within seven years of ratification, both countries would have to lower their deployed strategic warheads to 1,550. Ballistic missile launchers and bombers would be capped at 800. And, of those, only 700 could be deployed. The two countries would be responsible for verifying each other's cuts.
In Moscow, Foreign Minister Sergei Lavrov said the agreement was an important security step for both countries.
SERGEI LAVROV, Russian foreign minister (through translator): This is an absolutely honest position, which doesn't prohibit either side from making unilateral decisions. But it unequivocally means that strategic offensive armaments will be reduced to a degree which will ensure the security of each party.
JUDY WOODRUFF: For Mr. Obama, the agreement was essential in order to reset relations with Russia.
BARACK OBAMA: With this agreement, the United States and Russia, the two largest nuclear powers in the world, also send a clear signal that we intend to lead.
JUDY WOODRUFF: Defense Secretary Robert Gates said the deal doesn't jeopardize the U.S. defense posture.
ROBERT GATES, U.S. secretary of defense: The reductions in this treaty will not affect the strength of our nuclear triad, nor does this treaty limit plans to protect the United States and our allies by improving and deploying missile defense systems.
JUDY WOODRUFF: Two-thirds of the U.S. Senate are needed to ratify the treaty. Many Senate Republicans are insisting the pact not interfere with future plans for missile defense and weapons modernization.
Republican Jon Kyl of Arizona:
SEN. JON KYL, R-Ariz., minority whip: The point being that, if you draw down the number of weapons and weapon delivery systems, nuclear warheads and systems that deliver them, under this treaty, which will be done, then it is even more imperative that what you have left works and is safe and secure.
JUDY WOODRUFF: Presidents Obama and Medvedev are set to sign the pact in Prague on April 8.