Retired US Navy Admiral William McRaven. Photo by Robert Daemmrich Photography Inc/Corbis via Getty Images Retired Adm. William McRaven wrote in op-ed Monday saying that while he supports certain conservative ideals, he also believes in ideas like "Black lives matter." He wrote that he voted for Democratic presidential nominee Joe Biden because "we need a president for all Americans, not just half of America." During the Trump administration, McRaven has been an outspoken critic of President Donald Trump, who he has accused of harming American values and tearing down US institutions. Visit Business Insider's homepage for more stories. Retired Adm.