WASHINGTON — As he heads to Florida this weekend, President Donald Trump is following in the footsteps of former President Barack Obama, a man he loathes and a leader whose time in office in many ways came to be defined by mass shootings. Obama bequeathed on his successor an almost ritualistic response to gun tragedies, beginning with the 2011 attack on then-Rep. Gabrielle Giffords, D-Ariz., and ending with the 2016 Dallas attack that left five officers dead. There were 15 speeches from the White House, countless prayers for the fallen and more than a dozen visits to the crime scenes. […]