WASHINGTON — President Obama nixed a bill Friday that would have allowed the families of 9/11 victims to sue the government of Saudi Arabia, arguing it undermined national security and setting up the possibility that Congress might override his veto for the first time during his presidency.

The bill had sailed through both chambers of Congress with bipartisan support, clearing the final hurdle just days before the 15th anniversary of the 9/11 attacks that killed nearly 3,000 people. But the White House said the bill, which doesn’t refer specifically to Saudi Arabia, could backfire by opening up the US government and its officials to lawsuits by anyone accusing the United States of supporting terrorism, rightly or wrongly.

Previous attempts to overturn Obama’s vetoes have all been unsuccessful.

Associated Press