This fall in New Hampshire, a state with a strong independent streak, the open governor's race could hinge on the effectiveness of Democratic and Republican efforts to paint their opponents as too far to the left or right.

The reason? The candidates -- now in competitive primary races -- are still largely undefined in the minds of many voters, meaning each will have an opportunity to etch impressions in the minds of undecided voters.

Voters head to the polls Tuesday in the Granite State, where the primary campaigns have been underway for months in the race to replace popular Gov. John Lynch (D), who is retiring at the end of his two-year term.

On the Republican side, Ovide Lamontagne, an attorney and former gubernatorial and U.S. Senate candidate, is the frontrunner against conservative activist Kevin Smith. Democratic automated pollster Public Policy Polling's early August survey showed Lamontagne up by 28 points over Smith. Lamontagne's experience has also allowed him to raise and spend money at a rate that Smith hasn't been able to match.

The frontrunner in the Democratic race is former state Senate majority leader Maggie Hassan -- but this primary could be closer than the GOP contest. The PPP poll showed Hassan with a slight lead over former state senator Jackie Cilley. Hassan has the support of President Bill Clinton and some key labor organizations. She is viewed by national Democratic strategists as the stronger general election candidate. All that said, Cilley has remained competitive.

Looking ahead to November, two things are immediately clear:

First, the general election will be a tight race, no matter who wins each party's nomination. Both a University of New Hampshire Survey Center poll conducted for WMUR-TV in early August and PPP showed the general election match-ups were about even, regardless of the candidate pairings.

Second, as we said above, there are a lot of undecided voters and significant unfamiliarity with the field. The UNH poll (which, it's important to note, was conducted from Aug. 1-12, a longer time than usual for a poll to be in the field) showed that in every general match-up, at least a third of the electorate said they were undecided.

And with regard to overall opinion of the candidates, there was a definite wait-and-see sentiment: When the opinion of each individual candidate was tested in the UNH poll, the majority of respondents either said they had no opinion or were neutral.

The governor, who has burnished his centrist credentials over the years, remains popular, and both Democrats and Republicans will try use Lynch's appeal to their advantage. GOP strategists say they would move to cast Hassan or Cilley to the left of Lynch and that they believe the debate over the economy will grab more attention than social issues.

Democrats are ready to pounce on Lamontagne's reputation as a social conservative and would likely brand him as a far-right Republican. “Ovide Lamontagne is a perennial candidate who marches in lockstep with the extremist, Tea Party Republicans in Concord," Democratic Governors Association executive director Colm O'Comartun said last year after Lamontagne announced his bid.

Both parties will try to craft positive images of their nominees as consensus builders and independent thinkers. But attack ads usually attract more attention than positive ones, which could lead to a highly negative fall campaign.

Democrats are playing a lot of defense across the nation's gubernatorial landscape this cycle. Making key holds in states like New Hampshire will help determine whether the party is able to weather the storm or whether the GOP, boosted by the Republican Governors Association's huge cash advantage, will notch a big pickup.