WASHINGTON -- Mitt Romney won broad support from conservatives and moderates and was widely viewed as Republicans' best hope of defeating President Barack Obama in this fall's elections, preliminary exit polls of voters in Tuesday's New Hampshire primary showed.

The former governor of neighboring Massachusetts was the easy winner among the 6 in 10 voters who picked the economy as their top issue.

Given four choices, a third said the top quality they were seeking in a candidate was someone who could topple Obama -- and 6 in 10 of them said they'd backed Romney.

Regardless of whom they voted for, just over half named Romney as the GOP contender with the best shot at victory in November. Further underscoring his wide appeal, about 6 in 10 voters Tuesday said they would be satisfied with Romney as the party's nominee. Majorities said they would be unhappy if former Pennsylvania Sen. Rick Santorum, Texas Rep. Ron Paul or former House Speaker Newt Gingrich were the nominee.

Overall, about 2 in 3 voters expressed satisfaction with the field of GOP contenders, and nearly half of them backed Romney.

Nearly 4 in 10 conservatives backed him -- double his nearest opponents. And he held a slight lead among self-described moderates and liberals.

As he did last week in finishing third in Iowa, Paul drew strength from voters under age 30 and lower-income people. He also was the strong preference for voters looking for a true conservative and a candidate with strong moral character.

Paul also shared the lead with Romney among the 1 in 4 people seeking someone with the proper experience to be president.

Jon Huntsman, the former Utah governor, did best among tea party opponents -- an ominous sign for a candidate in a party where that conservative bloc of voters wield strong influence.

The exit poll showed disappointments galore for Santorum, who finished a whisker behind Romney in Iowa last week and has been hoping to emerge as the consensus conservative alternative to him.

Santorum won just small fractions of the votes of Catholics and working-class people, groups he has hoped to appeal to because of his own background.