Speaking at the U.S. Conference of Mayors in San Francisco Friday, President Barack Obama called for a national debate on gun regulations after the shootings of nine people at Bible study at a historic black church in Charleston, South, Carolina. "I refuse to act as if this is the new normal or to pretend that it's simply sufficient to grieve, and that any mention of us doing something to stop it is somehow politicizing the problem," Obama said. The president called out Congress for failing to pass "common-sense" gun safety reforms after the Sandy Hook massacre in 2012. "We don't know it would have prevented what happened in Charleston — no reform can guarantee the elimination of violence — but we might still have some more Americans with us," Obama said. "We should be strong enough to acknowledge this."