In the poll conducted after a gunman killed 17 people at a Florida high school last week, more than three-quarters, 77 percent, said they think more effective mental health screening and treatment could have prevented the shooting.

The Post-ABC poll also finds that 58 percent of adults say stricter gun control laws could have prevented the shooting at Marjory Stoneman Douglas High School, but there is no rise in support for banning assault weapons compared with two years ago and the partisan divide on this policy is as stark as ever. On the issue of whether allowing teachers to carry guns could have deterred the rampage, a proposal Education Secretary Betsy DeVos said is an option for schools, 42 percent said they agreed.