The bill requires the president to report every 60 days on Iran's latest nuclear capabilities, including an estimated timeline for when it could develop a nuclear explosive device and build a nuclear weapon, also known as "breakout capacity."
"What that gives you is a very firm red line," says Mark Dubowitz, a sanctions expert and executive director of the pro-sanctions think tank Foundation for Defense of Democracies.
It also requires the secretary of State to make a determination as to whether Tehran's paramilitary force, the Iranian Revolutionary Guard Corps, is a foreign terrorist organization.
The bill includes a section targeting human rights abusers, including those involved in the regime's program of censorship, and would apply financial-sector sanctions in existing law to transactions conducted by designated human rights violators.
The House legislation does not go as far as some sanctions hawks would like; a Senate bill that Kirk is working on is likely to pursue some of the legislation's targets more vigorously, Dubowitz says.
One key focus is barring Iran's access to euros.
Iran "has billions of euros' worth of foreign exchange reserves sitting in foreign financial institutions," which are the "principal weapon to forestall economic collapse," Dubowitz explains. With access to dollars restricted because of sanctions, those reserves are increasingly being converted to euros.
To access that money, however, Tehran needs the banks holding the funds to move them around, transfers that have to be settled and cleared through a European Central Bank payment and settlement system called Target 2.