Taking over as chairman of the National Governors Association, Gov. Phil Murphy on Friday announced a nationwide effort to strengthen mental health among young Americans, calling it a crisis “we must tackle together and now.” Officials and experts say the U.S. has been facing a mental health crisis made worse by the COVID-19 pandemic. Murphy’s office pointed to a study from the U.S. Centers for Disease Control and Prevention that found 37% of high school students reported poor mental health during the pandemic, while 44% reported persistent feelings of sadness or hopelessness. Each chairman of…