In the wake of the Orlando massacre and on the eve of a crucial Senate vote on a firearms bill that he says would “close a fatal gap,” Sen. Charles Schumer on Sunday called on Americans to “make their voices heard” by demanding that their congressional representatives improve gun-buyer background checks.

“These votes aim to fix the broken gun background-check system and prevent prohibited purchasers — like felons, domestic-violence offenders and terror suspects — from getting their hands on weapons of war through gaping loopholes in the law that currently exist and need to be closed,” Schumer said.