The initiative, launched by the mayor of Denver, Wellington Webb, is already being nicknamed the Million Mayor March in imitation of the Nation of Islam's Million Man March on behalf of African-Americans three years ago.
"It's time for Congress to respond to the wishes of the American people," Mr Webb said. His words carry a particular legitimacy, since Denver is just a half-hour drive from Columbine High School, the scene in April of the country's worst-ever school shooting. Mr Webb, an African-American liberal Democrat who has just been re-elected to a third term in office, is also president of the country's Conference of Mayors.
The march is planned for 9 September, the day most American children return to school after the summer holidays and an easy date to remember - 9.9.99. Columbine High School is resuming classes today, an emotional moment for students who have not been back to the building since Eric Harris and Dylan Klebold carried out the killings on 20 April.
Mr Webb said he was moved to action by last week's attack on a Jewish community centre in Los Angeles, in which a white supremacist shot three small boys, a teenager and an elderly woman, then shot dead a postman while making his getaway. "This issue is more important than tax cuts," the major said.
Mr Webb wants a rigorous system of background checks on buyers at gun shows, stricter rules on importing high- capacity ammunition clips and childproof locks on handguns. He will have the support of the Los Angeles police chief, Bernard Parks, who said over the weekend that assault rifles and cheap "Saturday-night special" handguns had no place in civilised society.
The Senate reluctantly approved background checks at gun shows in the wake of the Columbine shooting, but the provision is expected to be voted down again before it can become law.
Mr Webb attracted widespread attention when he urged the National Rifle Association, the country's powerful gun lobby, to cancel its annual convention in Denver, scheduled for 10 days after Columbine. When the NRA came, albeit with a drastically scaled-back agenda, Mr Webb led demonstrations outside the association's hotel.