Former President Barack Obama spoke out Friday against President Donald Trump’s continued claims that he can end birthright citizenship for children born in the U.S. to parents who aren’t citizens. “A president doesn’t get to decide on his own who’s an American citizen and who’s not,” Obama told a crowd in Florida while stumping for two Democratic candidates there: Andrew Gillum, the mayor of Tallahassee who is running for governor, and Sen. Bill Nelson, who is seeking a fourth term. “That’s not how the Constitution of the United States works,” added Obama, who once taught constitutional law at the University...