The Senate just voted by that overwhelming margin on a non-binding motion to back a foreign prime minister, Binyamin Netanyahu, over the president of the US, in declaring that the US would act if Iran gained a capability for a nuke, regardless of whether it decided to weaponize it:
The "capability" debate was initially framed as one over "containment" in February, and hawks like Graham found little bipartisan support until their position became a centerpiece of the AIPAC policy conference in March.
AIPAC does its work with unremitting diligence. I favor containment as the least worst option. But that obvious position is held by no-one in power in Washington. Including Obama.