Families of the victims of the 9/11 terrorist attacks are calling Sens. John McCain and Lindsey Graham’s efforts to alter a law that would allow them to sue Saudi Arabia for its complicity in the attacks a “betrayal.”

Congress passed the Justice Against Sponsors of Terrorism Act and overrode President Barack Obama’s veto earlier this year.

However, according to The Associated Press, Graham and McCain are trying to include an amendment so that only countries that knowingly engaged in terrorism can have lawsuits filed against them.

“We don’t want to be sued under those circumstances,” Graham told the AP.

In a statement, the 9/11 Families & Survivors United for Justice Against Terrorism said the senators’ proposal comes after a massive lobbying campaign from Saudi Arabia.

“Sen. Graham is now stabbing the 9/11 families in the back. He and Sen. McCain are seeking to torpedo JASTA by imposing changes demanded by Saudi Arabia’s lobbyists,” Terry Strada, the group’s national chairman, said in the statement. “We have reviewed the language, and it is an absolute betrayal.”