Democrats suffer an enthusiasm gap

That is not necessarily a predictor of victory in November — there’s a seven-week campaign to be run — but it puts the dominant Democratic Party in the unusual position of not only battling for critical independent votes but firing up its torpid base.

Because the primary was the first in memory without a contest at the top of the ballot in either party, overall turnout was the lowest by far for the past six gubernatorial cycles and slightly higher than the modern low in 1986.

But Republican turnout was exceptionally high in the 10th Congressional District, where there is an open seat; in many suburban and exurban areas of the Merrimack and Blackstone valleys; and in Worcester County.

The turnout in traditionally Democratic cities and many liberal areas, by contrast, was low to abysmal. In Boston and Cambridge, the number of voters casting Democratic ballots was less than half what it has been on average for the past seven gubernatorial primaries, a Globe analysis shows.

In a potentially troubling signal for Democratic Governor Deval Patrick, who built a diverse coalition of supporters in his 2006 victory, the turnout was especially light in Boston’s predominantly minority neighborhoods, despite two crowded Democratic primaries for open state House seats.

Democrats have a more than 3-to-1 registration average statewide, but in Tuesday’s primary, in which independents could cast ballots for either party, Democrats outpolled Republicans by only about 2 to 1. That’s the narrowest spread in the past 24 years. Even in cycles when Republicans won the governorship, GOP voters comprised more than 30 percent of the electorate only once in a primary — 1994, the year of William F. Weld’s historic re-election landslide.

In the 10th District, which stretches from Quincy to Cape Cod and the Islands, competitive primaries in both parties this year produced some of the highest turnouts in the state, with reported Democratic turnout exceeding the GOP by only 5 percentage points. That edge will increase slightly when Democratic results in five of the 199 precincts, still untabulated late yesterday, are added to the total.

That’s a significant improvement for Republicans, however. The last time the seat was open, in 1996, Democratic turnout exceeded Republican by nearly 40 percentage points, with multi-candidate primaries in both parties.

Jennifer Nassour, chairwoman of the Massachusetts Republican Party, said her party’s higher turnout “speaks volumes to the anger and frustration people are feeling now. ... People are fed up, they want everyone out, and the party in power are the Democrats.’’

Her Democratic counterpart, John Walsh, acknowledged that “in a couple of places, there was a pickup of this Tea Party enthusiasm.’’ But he said Massachusetts is different from other states.

“We’re not Sarah Palin, burn-the-house-down, Delaware or Alaska,’’ he said. “No doubt this is going to be an important and challenging election for incumbents everywhere, and it will depend on how well we do our work and talk to people and execute in campaign mode.’’

The state Democratic Party, he noted, started September with a $1 million advantage over the state Republican Party in cash on hand for the final weeks of the race.

But Democrats will have to spend wisely to counteract the increased Republican energy in many parts of the state.

In Haverhill, a Merrimack Valley city that is nominally Democratic but sometimes votes Republican in November elections, Democratic turnout has generally exceeded that of Republicans by a wide margin in primaries in the last six gubernatorial cycles. On Tuesday, it flipped, with voters casting more Republican ballots than Democratic ones, according to unofficial results.

Similarly, in Barnstable, the most populous town on Cape Cod, a swing area, Democrats averaged 57 percent of primary turnout in six previous gubernatorial cycles. On Tuesday, the percentage fell to 44 percent, unofficial tallies showed.