Executive Order 12170 was issued by American president Jimmy Carter on November 14, 1979, ten days after the Iran hostage crisis had started.
According to Gregory Korte of USA Today, this state of emergency gives "extra ordinary powers" to the president to "seize property, call up the National Guard and hire and fire military officers at will," since it is declared by executive order.
[2] By 2016 (the year the Joint Comprehensive Plan of Action was implemented), some of the executive orders issued pursuant to the declared national emergency were terminated.
[1] "Despite the historic deal to ensure the exclusively peaceful nature of Iran's nuclear program, certain actions and policies of the Government of Iran continue to pose an unusual and extraordinary threat to the national security, foreign policy, and economy of the United States," wrote Obama in his letter to the Congress.
"[4] On November 6, 2017, President Donald Trump extended the national emergency for another year and wrote a letter to Congress.