Any national election campaign in the vast United States needs an army of volunteer workers if it is to have much hope of success.
The billionaire Michael Bloomberg, a Democratic hopeful in this year's presidential race, went about recruiting his own "army" in an unusual way, relying on goodwill generated over the years by his own activism and his millions of dollars of charitable donations.
Healthcare, education, the environment, gun control... the former New York mayor -- one of the richest people in the world -- has long put his fortune in the service of those and other causes, financing organizations whose members are now more than willing to repay their benefactor through their own time and effort.
Among them are the many militant members of the group Moms Demand Action (MDA), an anti-gun violence campaign founded after the 2012 massacre at Sandy Hook Elementary School in Newtown, Connecticut.
They provide much of the energy behind the Everytown for Gun Safety lobbying group, which was founded -- and largely financed -- by Bloomberg. The group claims six million members nationwide.
"There's a lot of Moms Demand Action volunteers that are out canvassing for Mayor Bloomberg" because of his longtime support for gun control efforts, said Ruth Hoffman, a member of the group who had come to hear Bloomberg speak at a rally Saturday in McLean, Virginia.
"He saw it was an issue since 2005 and has been committed to the issue," she said. "I think that that says a lot about a person."
Because he skipped the first four voting states due to his late entrance into the race, Bloomberg is under heavy pressure to perform well on "Super Tuesday."
Bloomberg has spent some $10 billion on charitable works and political campaigns to advance the causes dearest to his heart, according to a New York Times investigation. (Even after that spending, he is estimated to be worth more than $60 billion.)
"We see the type of work that he's done," said Asieh Kehwari, an MDA member who attended Saturday's rally, "so I'm sure that we will definitely assist him."