Will a burst of new, young energy break an old impasse over gun laws?

For days now, the airwaves and social media have been filled with the voices of young people, thick with righteousness and anger, vowing never again.

But will the student-led protests against gun violence dramatically change the politics and lead the president and Congress to act in a way that other explosions of fury and grief - after Virginia Tech, Aurora, Newtown, Charleston, San Bernardino, Orlando, Las Vegas - have not?

It will take time - not the next few days or weeks, but months and even years - to know whether last week's slaughter of 17 people at Marjory Stoneman Douglas High School in