The White House is working with its allies on a well-financed campaign in Washington and around the country to shift public opinion toward stricter gun laws and provide political cover to lawmakers who end up voting for an assault-weapons ban or other firearm restrictions. …

The groups, whose leaders are in regular contact with the White House, are working to enlist religious leaders, mayors, police chiefs and other influential constituents to lobby their local lawmakers in their home districts. The organizations also plan to stage rallies at congressional town hall meetings across the country in much the same way tea party activists mounted opposition in 2009 to Obama’s health-care overhaul.

A trial run for the burgeoning campaign came this week when the Coalition to Stop Gun Violence ran hard-hitting ads in North Dakota and Capitol Hill newspapers against Sen. Heidi Heitkamp (D-N.D.), who said Sunday that some of the gun measures Obama is considering are “extreme.” After the ads — which told Heitkamp “Shame on you” — the freshman senator’s office issued a statement opening the door to supporting some gun-control measures. …

Other organizations active in the effort include liberal interest groups, labor unions and Mayors Against Illegal Guns, which is led and financed by New York Mayor Michael R. Bloomberg (I).