Sen. Tom Cotton was the only vote against the "Senate Compromise on Iran Nuclear Deal" bill

Sen. Cotton may be the only constitutional conservative left in the Senate. 

Via Slate:

For his part, Cotton released a statement denouncing the bill as wrongfully bestowing a "blessing" from Congress on the White House's approach to Iran:

A nuclear-arms agreement with any adversary—especially the terror-sponsoring, Islamist Iranian regime—should be submitted as a treaty and obtain a two-thirds majority vote in the Senate as required by the Constitution.  President Obama wants to reverse this rule, requiring opponents to get a two-thirds vote to stop his dangerous deal. But Congress should not accept this usurpation, nor allow the president any grounds to claim that Congress blessed his nuclear deal. I will work with Republicans and Democrats to stop a dangerous deal that would put Iran on the path to obtaining a nuclear weapon.