In October, former Marine Corps commandant retired Gen. James Conway warned the S-300's deployment "would be a game changer in the region." Iranian officials characterized the deployment of the system as defensive. "Our main priority is to protect Iran's nuclear facilities under any circumstances," said Brig. Gen. Farzad Esmaili, commander of the Islamic Revolutionary Guards Corps' air defense force. "Today, Iran's sky is one of the most secure in the Middle East." "The S-300 system is a defense system, not an assault one, but the Americans did their utmost to prevent Iran from getting it," Supreme Leader Ayatollah Ali Khamenei said. Sen. Tom CottonTom CottonState: US concerned about missile defense system at Iranian uranium facility GOP senators argue DOJ pressured Aetna on ObamaCare Trump, GOP see gold in Clinton Foundation attacks MORE (R-Ark.), member of the Senate Armed Service Committee, on Monday blasted the administration's Iran policy, saying it emboldened the "ayatollahs in Tehran" and led to the deal going through. "Had the Obama Administration not rushed to dismantle the international sanctions restraining Iran’s belligerence in the Middle East in pursuit of a legacy, Iran would not have been able to acquire and deploy such destabilizing weapons," he said.