Former Sen. Larry Pressler (R-SD) endorsed Hillary Clinton for president and called for universal background checks on all gun sales and an assault weapons ban in the wake of the deadliest mass shooting in U.S. history, The Hill reports.

Said Pressler: “I can’t believe I’m endorsing Hillary Clinton for president, but I am. This morning, I woke up and told my wife, ‘Did I really do that?’ But I did.”

He added: “If someone had told me 10 years ago I would do this, I wouldn’t have believed them.”