Four days before the “March For Our Lives,” six of the event's organizers who survived the mass shooting in Parkland urged young people to get involved in politics and unify around a common cause: ending gun violence across the country.

Speaking at Harvard’s Kennedy School of Government, they also had a message for elected officials who impede progress on gun reform.

“What’s important is that we make sure that we speak up to these congressman — these local and state legislators — and let them know that [this is] what their constituents want and that if you choose not to vote on the side of students lives that’s completely up to you,” said David Hogg, a senior at Marjory Stoneman Douglass High School. “And if you choose not to vote on the side of just human lives that are innocently taken, thousands of lives every year, that’s okay, because we will vote you out. It’s as simple as that.”

The discussion began with a moment of silence for the victims of the shooting at Great Mills High School in Maryland. Two students were injured on Tuesday — one critically — while the gunman, 17-year-old Austin Rollins, was killed by a school resource officer.

“These tragedies don’t seem to stop,” said Emma Gonzalez, another senior from Marjory Stoneman. “It is important that we acknowledge them.”

The event planned for Saturday is expected to draw massive crowds worldwide. More than 800 cities and towns will hold rallies asking elected leaders to enact reforms that will end gun violence across the country, not just in schools. Broadening the mission to encompass all types of gun violence was a conscience decision to unify people from different walks of life behind a common goal, the organizers said. 

"Every place in America needs to come together and stand up for this and make this the voting issue so that we can draw the line in the sand between the leaders who are there for them and their position and for profit and the people who are actually fighting for people's lives and to save us," said Matt Deitsch, who graduated from Marjory Stoneman in 2016. 

Which tragedies receive media coverage and serve as catalyst for change was a theme that dominated much of the evening. The students from Parkland acknowledged that they have been given a platform many survivors of gun violence from poorer, minority communities haven't. 

"If you look up on this stage you will notice that something is missing," Deitsch said. "It makes me absolutely sick that we're not sharing the stage right now, but I promise you that when you see us on Saturday we will be."

There are roughly 13,000 gun deaths in the United States each year, which breaks down to an average of about 96 a day. Most happen outside of schools. Measures like the STOP School Violence Act, which sets aside money for programs to make schools safer and passed the House of Representatives last week as students across the country staged a walk out to demand gun control legislation, don't go far enough, the panel argued, because shootings happen in churches, movie theaters and night clubs.

Polling after the Parkland shooting showed that 97 percent of Americans support universal background checks, 83 percent support mandatory waiting periods and 67 percent support a nationwide ban on the sale of assault weapons. Yet, progress on gun reform remains elusive.

Which brings the Parkland students back to our elected officials.

"Politicians work for us," said Alex Wind, a junior at Marjory Stoneman Douglas. "Call your congressman. Call your senators. Call your representatives and say, "If you do this, you will not be voted into office come November."

This article has been updated.