The men now rising through the security establishment have spent their careers confronting enemies abroad and suppressing dissent at home. The announcement of the senior appointments, purportedly made by Supreme Leader Mojtaba Khamenei on Monday, followed the naming of a new national security chief, Mohsen Rezaie, a day earlier. Most of the appointees have a background in intelligence, according to Saeid Golkar, associate professor of political science at the University of Tennessee at Chattanooga. “The picture we are seeing is the Islamic Republic moving toward a security-dominated bureaucratic regime,” he told CNN. “The current leadership in Tehran is far more risk-taking,” according to Vali Nasr, author of “Iran’s Grand Strategy.”