(CNN) -- Today, President Obama and Russian President Dmitri Medvedev signed a treaty fixing a ceiling for each country of 1,550 nuclear warheads and 700 deployed nuclear delivery vehicles. The new limits are about a third lower than the previous ones negotiated by George W. Bush in the 2002 Moscow Treaty of 2,200 per side. Some are impressed. Now that the new treaty is signed, it will be against the law for a president to deploy 1,600 warheads -- unless he first withdraws from the treaty. But a new "counting rule" undercuts the significance of Obama and Medvedev's achievement. Each bomber counts as only one warhead, even though each might be able to carry as many as 20 warheads.
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Jonathan Schell says U.S.-Russia treaty lowers ceiling for each country's nuclear arsenals
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But "counting rule" undercuts new limits, theoretically allows more weapons, he says
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Cuts are welcome, he says, but why continue balance of terror long after Cold War's end?
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Schell: Existence of thousands of nukes is failure that outweighs treaty's acheivement
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