Story highlights Political candidates are scrambling to communicate their support for gun safety, authors write

With the vocal majority of Americans behind us, our movement has reached a tipping point, they say

Gabrielle Giffords represented Arizona's 8th district in Congress from 2007 to 2012. Captain Mark Kelly (US Navy, retired) is a combat veteran and former NASA astronaut. They co-founded the gun violence prevention organization Americans for Responsible Solutions in 2013. The views expressed are their own.

(CNN) We knew we had to speak up -- and stand up.

It was December 2012, and 20 kindergartners and first graders had been murdered in their classrooms at Sandy Hook Elementary School in Newtown, Connecticut. It was as heartbreaking as it was senseless.

It was then that we decided to devote ourselves and our second chance at service to making our communities safer from gun violence. To do our small part, we'd help fight for better gun laws and policies that keep deadly weapons out of the hands of dangerous individuals while respecting the rights of law-abiding gun owners like us. It just seemed like the responsible thing to do.

Gabrielle Giffords and Mark Kelly

Since the tragedy at Sandy Hook Elementary School, we've founded a gun violence prevention organization, Americans for Responsible Solutions, and criss-crossed the nation, speaking out about the commonsense solutions, like closing loopholes in our criminal background check laws for gun sales, that have been proven to reduce gun violence and save lives.

We've met with gun violence survivors, legislators and testified before Congress. We've heard from those on the front lines of our national gun violence crisis. We've worked with veterans, law enforcement, businessmen and women, members of the clergy, and domestic violence prevention leaders.