If Congress rejects the deal:
- Iran will be back on the path to being a nuclear state with no restrictions on its nuclear infrastructure. Iran’s breakout time could very quickly shrink to zero.
- The U.S. will be blamed for the breakdown of negotiations, and other countries will abandon the sanctions regime.
- Neither Iran nor the other P5+1 nations will return to the negotiating table if the U.S. rejects an agreement supported by its negotiating partners and the entire UN Security Council.
- The inspections regime established under the interim agreement would disappear—and Iran’s nuclear program would be unverifiable.
- Iranian cooperation against ISIL in the Middle East could be jeopardized.
- The hardliners in Iran will be strengthened against the more moderate President Hassan Rouhani; the hardliners are more likely to win the next election.
- There will be extensive damage to the United States’ global reputation, threatening U.S. capacity to sustain multilateral agreements such as sanctions against Russia for its actions in Ukraine.
- U.S. failure to uphold its word could increase anti-American extremism and the terrorist threat to the United States.
- Calls from the U.S. military and Congress to launch military strikes against Iran would grow stronger, putting America on the path to another intractable war in the Middle East, as the choice will be Iran with a bomb or bombing Iran.
If the U.S. were to attack Iran with military force:
- An air campaign would at best set back Iran’s program for two to four years and would require repeated, costly bombing campaigns to disrupt Iran’s efforts.
- Iran would likely pursue a nuclear weapon covertly, relying on its scientific and engineering knowledge, which can’t be destroyed through the use of force.
- The U.S. would shoulder most if not all of the cost and risk, given that the U.S. would almost certainly be acting without NATO or Security Council approval.
- There could be direct Iranian retaliation against the U.S., Iranian missile or air attacks on Israel, or indirect retaliation by Hezbollah or covert, terrorist retaliation worldwide.
- There is likely to be increased global political and economic instability, including disruptions in energy supply and security.
- The attacks would be like pouring gasoline on the raging fires in the Middle East where many others would likely seek to advance their interests including, Turkey, Saudi Arabia, Russia and China.
- The Strait of Hormuz could be closed and could disrupt the oil market.