This Thursday President Barack Obama is scheduled to sign a follow on agreement to the Strategic Arms Reduction Treaty in Prague with Russian President Dmitri Medvedev. Since the day agreement on the new treaty was leaked by the Kremlin, the White House has been claiming that the treaty “does not contain any constraints on testing, development or deployment of current or planned U.S. missile defense programs.” And from day one the Russians have been saying the opposite.

Today in Moscow, Russian Foreign Minister Sergei Lavrov again made it clear that Russia does not share the same understanding of the treaty that the Obama administration does. Minister Lavrov told reporters that Russia maintains the right to exit the agreement if “the U.S.’s build-up of its missile defense strategic potential in numbers and quality begins to considerably affect the efficiency of Russian strategic nuclear forces. … Linkage to missile defense is clearly spelled out in the accord and is legally binding.”

“Trust but verify” was Ronald Reagan’s approach to relations with the Soviet Union. The Senate should keep that phrase in mind when working with the Obama administration while deciding whether or not they should ratify this agreement.