The statement by Sen. Jon Kyl (Ariz.) stunned the White House and Democrats, who scrambled to save the pact. It came just days after Obama declared that ratifying the treaty was his top foreign-policy priority for the lame-duck session of Congress.

The New Strategic Arms Reduction Treaty (New START) needs 67 votes to pass. Because of Democratic losses in the midterm elections, it would be harder to approve next year, requiring at least 14 Republican votes rather than nine now…

“Failure to pass the New START treaty this year would endanger our national security,” Biden warned in a statement Tuesday…

If the treaty were to fail, Obama’s ability to negotiate other treaties would be damaged, foreign diplomats say.