The Lonely Quiet

More Eli Saslow: In NEWTOWN, Conn. — They had promised to try everything, so Mark Barden went down into the basement to begin another project in memory of Daniel. The families of Sandy Hook Elementary were collaborating on a Mother's Day card, which would be produced by a marketing firm and mailed to hundreds of politicians across the country. "A difference-maker," the organizers had called it. Maybe if Mark could find the most arresting photo of his 7-year-old son, people would be compelled to act.

It hardly mattered that what Mark and his wife, Jackie, really wanted was to ignore Mother's Day altogether, to stay in their pajamas with their two surviving children, turn off their phones and…