U.S. President Barack Obama announced on Friday a new treaty with Russia to replace the Strategic Arms Reduction Treaty (START) that expired late last year.

However, considering the two nations' huge nuclear arsenals and sharp differences on missile defense systems, it remains unclear whether the treaty could be effectively implemented.

A massive cut

"After a year of intense negotiations, the United States and Russia have agreed to the most comprehensive arms control agreement in nearly two decades," Obama said in his speech to announce the treaty at the White House on the same day.

Negotiated to replace the START treaty that expired on Dec.5, the new agreement would update the mechanism for nuclear disarmament talks between the two sides.

According to the draft, the United States and Russia would reduce their deployed warheads to 1,550 respectively, while the cap on deployed ICBMs, SLBMs, and heavy bombers equipped for nuclear weapons is set at 700.

Information from the Russian media indicates that until 2009, the United States possessed 900 delivery vehicles and 3,500 nuclear warheads, though it only confirms a storage of 2,200, while Russia has 680 vehicles and 2,800 warheads.

Ulterior Considerations

"With this agreement, the two largest nuclear powers in the world also send a clear signal that we intend to lead," Obama said in his speech.

Steven Pifer, a disarmament expert with the Brookings Institution, said the new treaty, which will be signed April 8 in Prague, will better position the two countries in the upcoming Nuclear Security Summit in Washington D.C. on April 12-13 and the Non-Proliferation Treaty (NPT) Review Conference in New York in May.

"The advantage of this treaty is the American delegation is going to have a lot of credibility to ask other countries to find some ways to get past political differences, and come up with measures to strengthen the non-proliferation regime," Pifer said.

Nikolai Makarov, chief of the General Staff of Russia's armed forces, said in Moscow on Friday that the new treaty has dispelled the worries for each other and 100 percent matches the security interests of the Russian Federation.

Russian President Dmitry Medvedev said in a phone conversation with Obama that the treaty "reflects balance of interests of both states."

Questioned prospects

Presently, the combined nuclear weaponry at the disposal of the U.S. and Russia amounts to 95 percent of the world's total storage. The number would continue to stand above 90 percent should one third of those nuclear arms be destroyed as the treaty demands.

Taking their massive nuclear weapons stockpiles into account, the international community deems it's quite distant a goal to build a world free from nuclear arms.

What's more worrisome is that the two parties have been intensively divergent on the missile defense system in Eastern Europe, which fogs the treaty's future implementation.

Russian Foreign Minister Sergei Lavrov said Russia is entitled to suspend the reduction of its strategic nuclear weapons if the United States continue with its deployment of a missile defense system in Europe.

Congressional ratification is also a decisive element. For the treaty to be ratified, it has to win 67 votes in the 100-seat U.S. Senate.

Experts said the conservative senators have held from the beginning a consistent dissent over the treaty. In addition, the Republicans are on the peak of frustration over Obama administration's historic legislative victory in health care.

Thus, whether the treaty could receive enough support in the U.S. Congress is also in doubt.