Charlie Baker’s first run at the governor’s office was marked by an enormous 24-point loss among women. Since Baker’s 2010 loss, strong showings with women provided Massachusetts Democrats with decisive margins in a pair of US Senate races. Baker has made improving his standing with women voters one of the main thrusts of his current gubernatorial campaign. But as Baker works to reverse Republicans’ recent struggles with women, he’s also battling a surprising trend line — declining Republican fortunes with men.

Baker came up 6 points short in his 2010 challenge of Gov. Deval Patrick, despite winning men by a margin of 13 percentage points. Baker’s margin among men mirrored the margins posted by the last two Massachusetts Republicans to win statewide. Scott Brown won men by 14 points en route to his 2010 Senate victory, while Mitt Romney beat Shannon O’Brien by 13 among men in their 2002 gubernatorial contest.

Since the 2010 gubernatorial contest, though, statewide Republican candidates have seen their standing with men erode rapidly. CNN exit polls in Brown’s 2012 Senate matchup against Elizabeth Warren found Brown topping Warren by just 6 points among men. Two months of polling in the 2013 Senate special election between Gabriel Gomez and Ed Markey put Gomez, the Republican, ahead of Markey, the Democrat, by a single percentage point among men. (There was no exit polling and no post-election polling of voters in that race.)

This sharp 12-point swing sticks out because, at the same time that Republicans’ standing with men was eroding, Democrats’ margins among women remained stable. A MassINC Polling Group post-election poll found Patrick beating Baker by 24 points among women in their 2010 tilt. The 2012 CNN exit polls had Warren beating Brown by 18 points among women, while the 2013 Senate polling gave Markey a 20-point edge with women.

Lopsided margins with women have been a hallmark of Democratic victories in Massachusetts since Patrick’s 2006 romp into office. And the women’s vote looms large in any contest, since women make up the majority (between 52 and 54 percent) of the state’s electorate. But the recent swing away from the GOP among men complicates an already difficult demographic path Massachusetts Republicans have to walk. Baker is being hemmed in on both sides of the gender gap: the women’s vote has been stable and strongly stacked against Republican candidates, while the men’s vote is sliding toward Democrats.

Republicans’ recent slippage with men is also noteworthy because even a 13-point victory among men wasn’t enough to push Charlie Baker into the governor’s office four years ago. Baker needs to reestablish the strong showings Republicans made with men in 2002 and 2010, and he needs to eat into Democrats’ large margins with women.

Recent polling indicates Baker has work to do on both fronts.

This week’s WBUR/MassINC Polling Group poll found Baker with just a 4-point lead among men in a hypothetical matchup against Martha Coakley, while Baker trailed Coakley by 20 points among women. The last 10 gubernatorial polls, released by WBUR, the Boston Globe and UMass Lowell, show Coakley leading Baker by an average of 20 points among women, while Baker holds, on average, a 9-point lead among men.

Coakley has enjoyed a commanding lead in Democratic primary polls all summer.

This story was cross-posted to Poll Vault, a data-driven look at the 2014 election produced by WBUR and The MassINC Polling Group.