In an ad running in Pennsylvania, the Independence USA PAC backed by Mayor Michael Bloomberg claimed "Toomey crossed party lines… to stop gun sales to suspects on the terror watch list."

This ad is misleading at its core, largely because a measure to stop gun sales to suspects on the terror watch list never passed. Toomey’s own bill failed to garner significant support from either side of the aisle. Though he voted for the Collins amendment which had bipartisan support, that amendment was drafted by a Republican.

In the end, Toomey voted with his party when he voted against Feinstein’s bill and in favor of Cornyn’s. We rate the claim Mostly False.