The Anti-Ballistic Missile (ABM) Treaty, a relic of the cold war, officially expires on Thursday. The decades-old agreement which has served as a foundation of nuclear arms control had its critics and supporters and has remained controversial through the years.
The ABM Treaty was signed by then-U.S. President Richard Nixon, and Soviet leader Leonid Brezhnev in 1972. Thirty years later, the treaty has outlived its usefulness as both nations deal with new challenges in the post-cold war era.
When the ABM Treaty was signed, the United States and Soviet Union were taking the first steps at limiting, although not yet reducing, the size of their huge nuclear arsenals.
With both sides using nuclear weapons as a form of deterrence, the ABM Treaty sought to place limits on anti-missile systems that either side could deploy to protect their homelands. If either side, the thinking went, knew it could suffer intolerable nuclear retaliation, then neither would launch a first strike.
Both the United States and Soviet Union were permitted to protect just one site. Moscow had long before built a missile protection system to protect the capital. The United States eventually deployed a system to protect long-range nuclear missiles or ICBMs, but this was abandoned in the 1970s.
About 30 years later, in his campaign for president, George Bush called for accelerating development of a national missile defense system to shield the U.S. against new emerging threats.
North Korea's suspected nuclear weapons effort, as well as concern about missile and nuclear proliferation to other so-called "rogue states" provided further impetus.
The events of September 11 were an additional backdrop for Mr. Bush's announcement last December that the United States would exercise its option to withdraw from the ABM Treaty.
Russia, along with U.S. allies in Europe, initially opposed the move. Critics said withdrawal from the ABM Treaty, combined with missile defense, could spark a new arms race.
Opposition faded, but critics of the president's policies continue to hammer away at missile defense, saying it is too complex and expensive.
One such critic is Randy Forsberg, director of the Institute for Defense and Disarmament Studies in Cambridge, Massachusetts. "Bush's withdrawal from the ABM Treaty, and massive funding for national missile defense are likely to spar a nuclear build-up in China, which could trigger increases in India and Pakistan," she said.
As the ABM Treaty faded into history, a group of about 30 U.S. lawmakers tried to block its demise. Democratic Ohio Congressman Denis Kucinich maintained in this speech on the House floor, that Mr. Bush had overstepped his authority.
"The president, by withdrawing from this particular treaty, insists that he has the authority to terminate any treaty, and can do so without the consent of Congress," said Mr. Kucinich. "But according to Article Six, Clause 2 of the Constitution, treaties constitute the supreme law of the land. And the president does not have the authority to repeal laws."
Republicans who control the House, disagreed. Mr. Kucinich's effort to force a vote on the issue was defeated by a vote of 254 to 169. But he was not through, and filed a lawsuit in the U.S. District Court in Washington, claiming that only Congress can abrogate international treaties.
Meanwhile, on the very day U.S. withdrawal from ABM takes effect, the United States was due to conduct the next in a series of tests in its missile defense program.