Progressive advocacy group MoveOn.org came out with more Senate candidate endorsements on Thursday, throwing its large grassroots backing behind Sen. Sherrod Brown (D-Ohio) and Reps. Tammy Baldwin (D-Wis.) and Mazie Hirono (D-Hawaii).
"Tammy, Sherrod, and Mazie are some of the most passionate fighters for the 99% in Washington today," MoveOn's campaign director, Daniel Mintz, said in a statement. "If we send Sherrod back to the Senate this year, and elect Tammy and Mazie to join him, working families all across the country will be able to sleep easier, knowing they have leaders who are fighting for them -- not for special interests -- in our nation's capital."
The group had already endorsed Democratic Senate candidates Elizabeth Warren in Massachusetts and Rep. Chris Murphy, who faces a Aug. 14 primary, in Connecticut.
MoveOn said it will give its favored candidates grassroots support both online and on the ground.
Ninety-seven percent of MoveOn's Wisconsin members voted to endorse Baldwin, 96 percent of Ohio members backed Brown, and 79 percent of Hawaii members voted for Hirono.
Hirono still faces a primary challenge from former congressman Ed Case. A June poll found the two tied. The poll also found Hirono ahead by five percentage points in a potential general election contest with the presumptive GOP nominee, former Hawaii Gov. Linda Lingle.
Brown leads his race against Ohio state Treasurer Josh Mandel (R) by about seven points, according to a HuffPost Pollster analysis of several polls. The Democrat is ahead even though outside groups, including the U.S. Chamber of Commerce and Crossroads GPS, have poured an estimated $13 million into the race on Mandel's behalf.
In potential match-ups with GOP challengers, Baldwin fares worse than Hirono and Brown. There are four Wisconsin Republicans competing in the Aug. 14 primary. Businessman Eric Hovde and former Gov. Tommy Thompson are leading the field. A recent Public Policy Polling survey showed Baldwin trailing Hovde 44 to 45 percent and tying Thompson at 45 percent each.