Saudi Arabia has launched an expensive campaign to counter Congress’s decision to allow families of the victims of the 9/11 attacks to sue the kingdom in U.S. courts over its alleged funding of the 2001 hijackers. Many opponents of the Justice Against Sponsors of Terrorism Act, which passed in September, have still not revealed their funding, but the Associated Press reports the Saudis have been paying hundreds of thousands of dollars for U.S. military veterans to visit Capitol Hill to warn lawmakers about the bill’s potential consequences. Critics say the measure would expose U.S. troops and diplomats to lawsuits that otherwise couldn’t be filed because of sovereign immunity. While the bill passed the House and Senate with overwhelming support last September, President Obama vetoed it. Many of the recruited veterans were seemingly unaware that Saudi Arabia was paying for their travel and efforts. Organizers did not notify the Justice Department about the kingdom’s role in the campaign until months afterward, despite a World War II-era law that requires U.S. lobbyists to reveal payments from foreign governments.