Is Steve Grossman Closing?

Steve Grossman supporters are excited about a new poll released Monday from Suffolk University and the Boston Herald, which suggests a closer Democratic primary race than previous polls have shown. It has Martha Coakley with 42 percent, Grossman 30 percent, and Don Berwick 16 percent, with 12 percent undecided.

This poll was taken August 21 through 24, which makes it more recent than others—such as the Boston Globe/SocialSphere weekly poll—that show Coakley holding a more substantial lead. That Globe poll has shown some tightening as well, as undecided voters appear to have been breaking toward Grossman. In that poll, Coakley’s share of the primary vote remains steadily at 45 percent, while Grossman has climbed to 24 percent.

The Herald/Suffolk poll is not quite the same set of poll respondents, however. It used a very heavy screen for the most likely voters. For starters, it contacted only those who voted in three of the last four competitive statewide Democratic primaries: 2002 gubernatorial, 2006 gubernatorial, 2009 Senate special, and 2013 Senate special. Then, the pollsters used screening questions about likelihood of voting, and awareness of the upcoming primary.

The result is a group of respondents who represent the most devoted Democratic primary voters in the Commonwealth. Here’s an example: in this poll, 41 percent had never heard of Don Berwick, while 33 percent knew enough to give an opinion of him. In the latest Globe/SocialSphere polling, 64 percent of likely Democratic primary voters had never heard of Berwick, while 22 percent could give an opinion. That difference is not because people suddenly learned a lot about Berwick in the few days in between those polls.

That doesn’t mean one is right and the other is wrong. We don’t know what the actual voter turnout will end up looking like.

What we do know is that this reflects a difference that’s so apparent during this campaign: a marked difference between hardcore, super-active Democrats, who are skeptical of Coakley; and rank-and-file Democrats, who are perfectly happy with her. Sixty percent of the Herald/Suffolk respondents hold a favorable view of Coakley; 72 percent of Democrats in the Globe/SocialSphere poll do.

Thus, the more the primary looks like the small number of super-active voters, the better for Grossman; the more it includes rank-and-file Democrats, the better for Coakley.

It’s unlikely the primary will be as narrow as this Herald/Suffolk poll looks like. There can’t be more than 250,000 or so voters who fit their criteria in the state, and I’d be surprised if the actual primary turnout is much below 600,000. But, it’s also possible (and some are arguing to me) that the rank-and-file Democrats will end up behaving more like the super-active ones, after they start paying attention and becoming more informed in the final two weeks before the primary.

Maybe, but I doubt it. These are people who, in overwhelming numbers, give favorable ratings to Coakley, Deval Patrick, Elizabeth Warren, and Barack Obama, regardless of any bad news that pops up. They are happy with the Dems they know, and there just isn’t enough reason out there for them to change that view now.

The good news for Grossman is that there is evidence, between this and the Globe poll, that he has been picking up some of the undecided vote as people make up their minds. The bad news is that there is no evidence so far (emphasize, so far) that Coakley is losing any of her share of the vote—which appears to be plenty to win in a three-way primary regardless of how the undecideds break.