Senator Brian Schatz’s campaign says it will announce its latest endorsement on Sunday — this time from the National Association of Letter Carriers.

His campaign said today he’ll be addressing the union’s convention Sunday morning at the Waikiki Marriott.

Schatz was a co-sponsor of a Senate bill to maintain Saturday service. Hanabusa, though, co-sponsored a House resolution saying the U.S. Postal Service resolution saying the U.S. Postal Service should take all appropriate steps to continue Saturday mail delivery.

The union is classified as a “Heavy Hitter” by the Center for Responsive Politics, which means it was one of the top 140 contributors in the last federal elections. The union gave $2.9 million to candidates, including $10,000 to Sen. Mazie Hirono.

The endorsement is the latest in a number of Schatz has garnered thus far, including many from labor groups including he Hawaii Firefighters Association, United Food and Commercial Workers Local 480, Hawaii Building & Construction Trades Council, Plumbers Local 675, Elevator Constructors Local 126, Drywall, Tapers and Finishers Local 1944, Glaziers Local 1889, Boilermakers Local 204, Painters and Allied Trades Local 1791, IBEW Local 1186, Heat and Frost Insulators Local 132, Teamsters Local 996, Roofers Local 221, Iron Workers Local 625, IBEW Local 1260, University of Hawaii Professional Assembly, and the National Weather Service Employees Organization.

— Kery Murakami