The White House refused to rule out Wednesday whether President Obama might grant a pardon to Hillary Clinton to spare her from President-elect Donald Trump prosecuting her after he takes office. White House press secretary Josh Earnest said Mr. Obama is hopeful that Mr. Trump will follow long-standing tradition of not punishing political opponents through the criminal-justice system. He said all clemency actions go through a formal process, and that will remain in place until the end of Mr. Obama’s presidency in January. “The president has offered clemency to a substantial number of Americans who were previously serving time in...