Washington (CNN) -- Former Secretary of State Colin Powell on Wednesday joined a growing list of former GOP diplomatic and national security heavyweights endorsing the new Russian arms control treaty negotiated by the Obama administration.
Meeting with President Barack Obama in the Oval Office, Powell said he "fully" supports passage of the New START treaty as a way to reduce the threat of nuclear proliferation.
The accord is critical to maintaining the sort of "transparency" and "visibility" that helped promote trust and cooperation between the world's two nuclear superpowers in the past, he said.
The START treaty would resume mutual inspections of U.S. and Russian nuclear arsenals, while limiting both nations to 1,550 warheads and 700 launchers each.
Obama has called ratification of the treaty an immediate priority for the lame-duck Senate, saying it's critical to national security and a cornerstone of U.S.-Russia relations.
Several GOP senators led by Arizona's Jon Kyl, however, have urged the Senate to delay considering ratification until the next Congress, due in part to concerns about the current Senate workload and the need to modernize the U.S. nuclear arsenal.
Top Democrats fear that they will not find the 67 votes necessary to secure ratification in next year's more Republican Senate.
Powell has joined George Shultz, Lawrence Eagleburger, Henry Kissinger and James Baker -- all former Republican secretaries of state -- in authoring an opinion piece in support of the treaty that is scheduled to be released Thursday.