Cruz says the United States should not be backing any U.N. action until Congress fulfills its legal role in reviewing—and potentially rejecting—the deal, which will provide Iran with billions of dollars in economic relief.

Under the parameters of the deal, the United States and other global powers have agreed to rollback U.N. restrictions on Iran’s importation of weapons and previous obligations to fully halt uranium enrichment work, heavy water work relevant to the development of a plutonium-based weapon, and the construction of ballistic missiles.

Cruz says none of these restrictions should be lifted before Congress has fully reviewed and voted on the deal. Legislators have legally been given 60 days to do this.

However, the nuclear deal inked in Vienna this week makes no mention of the law giving Congress the power to review the deal. Instead, it assumes that Congress has already signed off.