WORCESTER — Delegates to the state Democratic convention this weekend did a groundbreaking thing. They nominated a candidate for governor who is sure to appeal to suburban-independent voters. In her convention speech to delegates, gubernatorial candidate and State Treasurer Shannon O’Brien’s expressly stated the value of these voters: "To win, we need to nominate a leader with unquestioned Democratic values, with a proven record as a strong fiscal manager, and the ability to attract independent voters to our side of this important fight. I am that leader." By recognizing independents’ importance in making their choice, delegates upended the conventional wisdom about what takes place at the party convention, generally home to the most hard-core, ossified type of Democrat.

Nothing in the daily newspaper or television news reports hinted at the significance of what, in time, might be considered a seminal event. But O’Brien’s winning the convention nomination thoroughly contravened what had seemed the likely outcome in the hours before the convention. On Friday night, all the old-timers were talking about Maurice Donahue of Holyoke, the politically powerful Senate president who won the 1970 gubernatorial nomination only to lose to Boston mayor Kevin White in the primary; White, in turn, lost to Republican Frank Sargent in the general election. The analogy was clear to long-time observers of state politics: if O’Brien lost the convention to Senate president Tom Birmingham (the Donahue figure in this race), she’d simply fight her way to a primary win in September with the support of suburban-independent voters.

When O’Brien accepted the state Democratic convention’s nod on Saturday, she foiled that story line. While the daily coverage focused on the candidates’ delegate-swapping and O’Brien’s out-slugging Birmingham, the significant event in the long term was the party regulars’ willingness to select a candidate who spoke so explicitly to voters outside the Worcester Centrum, let alone those outside the Democratic Party.

Now that all five candidates — O’Brien, Birmingham, former secretary of labor Robert Reich, former Democratic National Committee chair Steve Grossman, and former Watertown state senator Warren Tolman, each of whom represents a slightly different ideological strand — are on the ballot, the Democratic primary is poised to be what historians and political scientists call a "watershed election." In such an election — the presidential contests in 1992 and 1980 are examples — the selection of a certain candidate heralds long-term changes in voting patterns. In 1992, then–Arkansas governor Bill Clinton showed national Democrats that a centrist path could lead to victory. In 1980, Ronald Reagan defeated President Jimmy Carter by appealing to blue-collar voters ("Reagan Democrats"). In this same way, the 2002 governor’s election will settle a key question in Bay State politics: what kind of Democrat does the party need to defeat the Republicans for the first time in 12 years? Will it be a suburban-oriented fiscal moderate, such as O’Brien or Grossman? An innovative reformer, like Reich or Tolman? Or an old-school, urban lunch-pail type, like Birmingham? As far as the delegates at the convention were concerned, the answer was O’Brien.

Significantly, O’Brien’s third-ballot victory came, in part, as a result of her commitment to her lieutenant-governor pick, venture capitalist, former congressional candidate, and self-proclaimed "New Democrat" Christopher Gabrieli. Because O’Brien’s disciplined whips and field organization convinced her delegates to stay and vote for Gabrieli in the lieutenant-governor fight, her supporters were still present during the third ballot, when many delegates for the other candidates had left, and thus were able to propel O’Brien to a 53 to 47 percent victory over Birmingham — who delivered a steadfastly traditional Democratic-convention speech. And, as if to signal her awareness that the state is ready to revamp its politics, O’Brien herself invoked Clinton in her convention speech, saying this year "reminds me of the presidential campaign in 1992 [when] Clinton won because he showed that Democrats could demand fiscal responsibility and promote a progressive agenda that puts people first." What made her victory especially important is that she alone made a convention speech explicitly aimed at the independent voters who make up 51 percent of the state’s electorate and who are the key swing voters in state elections (see "Talking Politics," News and Features, May 31).