The Iranian government has racked up nearly $18 billion in court judgments in Washington since 2008 for support of terrorist attacks. But Iran has yet to pay a dime, and victims’ lawyers are expressing frustration at their lack of options.

Congress approved legislation five years ago to raise the stakes in civil terrorism lawsuits and make it easier to collect on judgments. Since then, the dollar amounts have gone up, but judgments remain largely unsatisfied.