The head of the U.S. Department of Homeland Security this week strongly defended how his agency is dealing with what he sees as threats to the country. Former Marine general John Kelly said he is tired of the criticisms directed at his workers by some members of the media, lawmakers and others. He said his agents are just enforcing the law. And his agents are protecting Americans. “Make no mistake, we are in fact a nation under attack. We are under attack from people who hate us, hate our freedoms, hate our laws, hate our values, hate the way we simply live our lives.” Kelly spoke Wednesday at George Washington University in Washington, D.C. He said his department’s stronger enforcement of immigration laws has led to a drop in the number of detentions of people trying to cross into the southwestern United States from Mexico. He says that helps people on both sides of the border.