The United States and Russia will sign a treaty on Thursday further reducing both countries' nuclear stockpiles. President Barack Obama and Russian President Dmitry Medvedev will meet in in the Czech capital, Prague to sign the treaty. The signing is expected to boost each country's national security and strengthen the U.S.-Russian relationship. The agreement to be signed replaces the START-1 treaty, which U.S. President George H.W. Bush and Soviet President Mikhail Gorbachev signed in 1991. It expired last December. After a year of tough negotiations, Mr. Obama and Mr. Medvedev will sign the treaty to shrink each country's arsenal of strategic deployed nuclear warheads by 25 to 30 percent. After the signing, the treaty must be ratified by the Russian Duma and the U.S. Senate, where 67 of the 100 Senators must approve it. During his brief stay in Prague, Mr. Obama will also have a one-on-one meeting with his Russian counterpart, and will have dinner with the heads of state of 11 Central and Eastern European countries.<br/>