By Sarah N. Lynch WASHINGTON (Reuters) – Merrick Garland, sworn in as U.S. attorney general on Thursday, pledged that the Justice Department would adhere to “norms” to earn the trust of the American people, alluding to Democratic complaints of its politicization under Republican former President Donald Trump. Garland, who had served as a federal appellate judge and federal prosecutor before President Joe Biden nominated him as the top U.S. law enforcement official, addressed department employees a day after the Senate confirmed him to the post. “The only way we can succeed and retain the trust…