WASHINGTON — Taking the reins at the Justice Department, Attorney General Merrick Garland sought Thursday to assure career staffers that he would prioritize restoring the department’s reputation for political independence and ensuring equal justice after a tumultuous four years under former President Donald Trump.“The only way we can succeed and retain the trust of the American people is to adhere to the norms that have become part of the DNA of every Justice Department employee,” Garland said in his first address to the …