SAN FRANCISCO — President Barack Obama on Friday said a mass shooting at a black church in South Carolina exposed the “blight” of racism still present in America, and railed against critics who have accused him of politicizing a tragedy to talk about tougher gun laws. Obama, speaking to the US Conference of Mayors, said the murder of nine people at an historic African-American church in Charleston shows the need for vigilance against racism. “The apparent motivations of the shooter remind us that racism remains a blight that we have to combat together,” Obama said. But he invoked other recent mass shootings at a school in Newtown, Connecticut and movie theater in Aurora, Colorado to argue for the need for reforms to gun laws, a politically fraught subject in a country whose constitution guarantees the right to own guns. “We should be able to talk about this issue as citizens without demonizing all gun owners who are overwhelmingly law abiding, but also without suggesting that any debate about this involves a wild-eyed plot to take everybody's guns away,” Obama said. Obama pushed for tighter controls on guns after the 2012 school shootings in Newtown, but was foiled by the politically power gun lobby and failed to convince Congress. Noting more than 11,000 Americans were killed by gun violence in 2013, Obama acknowledged that his failed proposals “wouldn't have prevented every act of violence” but said they would have stopped some of them. “You don't see murder on this kind of scale, with this kind of frequency, in any other advanced nation on earth,” he said. “Every country has violent, hateful or mentally unstable people. What's different is that not every country is awash with easily accessible guns,” he said. Obama said it is unlikely that Congress will work on new gun safety laws in the near future, but said he believes public opinion eventually will shift and compel lawmakers to act. “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 doing something to stop it is somehow politicizing the problem,” Obama said. Advocates of stricter gun laws introduced legislation less than two weeks before the Charleston shooting to encourage tougher state handgun licensing rules, but it stood little chance of advancing in the Republican-controlled Congress. Democratic Representative Chris Van Hollen, a backer, said, “We would hope that these kinds of tragedies would ultimately penetrate the consciousness of lawmakers and prompt action.” Brian Malte, an executive at the Brady Campaign to Prevent Gun Violence, a pro-gun control group, appeared less hopeful. “All Congress has done is block hearings and block votes on this issue,” Malte said. “You have too many corporate gun lobby lap-dogs in Congress who take money and don't support background checks,” he said. — Reuters