The Republican's death spiral is getting pretty ugly when a newbie senator can get 47 senators to sign a letter to Iran. Each senator must be running too scared to oppose even the most egregious exercise in stupidity.
But each time the party is subjected to some new absurdity by it's own members, the Republican brand nosedives and takes everyone with it. Besides the senators, Perry, Jindal, and Bush have backed the letter. It will become another "litmus test" of doctrinal purity for presidential candidates.
At this point, the Republicans have lost control of their representatives and I don't see how they can field a presidential candidate with any chance of winning in this atmosphere. It will be down and dirty the whole way.