The former mayor of New York City, Michael Bloomberg, is spending $50m of his own money to campaign for stricter gun laws.
He launched a new group called "Everytown", which is employing the strategy of gaining support from voters across the country, instead of political lobbying.
But the group has to overcome opposition from the National Rifle Association,which begins its annual conference on Friday.
Al Jazeera's Cath Turner reports from New York.
Source: Al Jazeera