Updated 7:20 a.m. Friday

A draft resolution being circulated by two moderate Democratic senators would give the government of Syrian President Bashar al-Assad 45 days to sign an international chemical weapons ban or face the threat of "all elements" of U.S. military power.

Sen. Heidi Heitkamp (D-N.D.). (LM Otero/AP.)

Sens. Joe Manchin III (D-W.Va.) and Heidi Heitkamp (D-N.D.) are working on the alternative proposal, which would delay the immediate use of military force and compel the Obama administration to build more international and American political support for striking the Assad government, according to Senate aides familiar with the talks.