(Reuters) - Senior White House officials responsible for navigating the administration through a trio of scandals met on Thursday with outside Democratic strategists for advice on how to get past the controversies and back on track advancing the president's agenda. The White House is trying to regain the upper hand after being knocked on the defensive over its response to deadly attacks in Benghazi, Libya, the seizure of journalists' phone records in a Justice Department leak investigation, and the Internal Revenue Service's targeting of conservative groups for special scrutiny. Now, President Barack Obama's closest advisers want to find a way...