President Obama’s old campaign team returned to the gun control beat with a message from the father of a student killed at Columbine High School to rally supporters for a gun control action week.

“These tragedies keep happening, and so far, Congress has failed to take common-sense action to stop them — even though nine in 10 Americans have agreed that expanding background checks would help close the loopholes that put guns in the hands of dangerous people and prevent future violence,” Tom Mauser said in an Organizing for Action email after describing his son Daniel, who died in the shooting at Columbine High School in 1999.

“Today, OFA and allied organizations are standing up for a national Day of Action to ask members of Congress: What will it take to finally act to prevent gun violence?”

The message coincides with calls for gun control in the United States from international figures following the Friday’s murder of an Australian citizen who played college baseball in Oklahoma.

“People thinking of going to the USA for business or tourists trips should think carefully about it given the statistical fact you are 15 times more likely to be shot dead in the USA than in Australia per capita per million people,” said Tim Fischer, the deputy prime minister of Australia.