WASHINGTON – Sen. Bill Nelson joined a large rally outside the Capitol in solidarity with the National School Walkout and urged students to "keep on speaking out."

"We are grieving in Florida and now you are giving voice to that grief," the Florida Democrat said. "And when you march on March 24, it's going to be a visible expression of the grief that we've been through.

"It's common sense that we should have universal background checks. And it's common sense that we should get the assault rifles and the banana clips off the streets. Keep on marching and keep on speaking out."

But while student activism remains strong, those kinds gun measures have no life on Capitol Hill.

Nelson has joined with Sen. Marco Rubio on some measures, including a school safety bill and gun violence restraining orders.

Rubio appeared at a Senate Judiciary Committee meeting on the Parkland shooting and mentioned the student walkout.

"Today, across the country, in a few minutes, students from across America will be exercising their First Amendment right to speak out about changes that they want on how we regulate our Second Amendment right. It's an interesting lesson in civics and in our constitutional process, which of all the committees in the Senate, this one understands better than any. And more than any other committee in the Senate, this committee also understands the difficulties and the political back and forth that occurs, the difference—the strong, well-intentioned differences of opinion that exist about how to regulate that Second Amendment. But the one thing I believe we do have common ground on is that I know of no one, I know of no one in this country who wants to see another community or another state endure such senseless violence."