Lisbeth Gronlund, senior scientist and co-director, the Global Security Program at the Union of Concerned Scientists

In his speech at Berlin’s Brandenburg Gate this morning, President Obama announced that the United States will work with Russia to reduce the number of both countries’ deployed strategic nuclear weapons as well as the number of US and Russian tactical weapons in Europe. 
We applaud this step. The Berlin wall fell more than two decades ago, and these reductions are long overdue. The president’s initiative implicitly acknowledges that today nuclear weapons are a liability, not an asset. 
However, the United States need not wait for Russia to reduce its nuclear arsenal. It can maintain a robust deterrent with less than 1,000 nuclear weapons—including strategic and tactical, deployed and stored—independent of Russia’s arsenal. Maintaining more weapons than needed undercuts U.S. security and wastes taxpayer dollars. These reductions should be accompanied by other measures to bolster national security and distance ourselves from outdated, Cold War thinking. For example, the United States still maintains nuclear land-based missiles on high alert so they can be launched quickly in the event of an attack. This practice is dangerous because it increases the risk of a Russian accidental or inadvertent launch, which could destroy the United States as a functioning society. It is also unnecessary because US nuclear missiles on submarines are invulnerable to attack and provide an overwhelming deterrent. Accordingly, the United States should eliminate its launch-under-attack options and urge Russia to follow suit. Finally, in conjunction with the president’s speech, the White House issued a fact sheet on Wednesday morning that stated the administration is narrowing the focus of US nuclear strategy to “only consider the use of nuclear weapons in extreme circumstances to defend the vital interests of the United States or its allies and partners. President Obama should go further by declaring that the only purpose of nuclear weapons is to deter, and if necessary respond to, the use of nuclear weapons by another country.