After the mass shooting at Marjory Stoneman Douglas High School that killed 17 people in February, President Trump vowed to train and arm teachers to secure schools and stop future massacres.

Many teachers and their unions fiercely rejected the president’s suggestion, but one Stoneman Douglas educator, Sean Simpson, said he would consider it.

“There are some of us that are willing to take the training if it was offered and probably be another line of defense,” Mr. Simpson, a chemistry teacher, told MSNBC a week after the shooting at the school, in Parkland, Fla. He cautioned, however, “I’m not sure if it’s the answer.”

This past weekend’s events may provide a clue. Mr. Simpson was charged on Sunday with failing to safely store a weapon after he accidentally left his Glock 9 millimeter handgun at a beach restroom, the Broward County Sheriff’s Office said.