EXIT POLLS: Clinton Backers Send Parting Shot to Obama

Barack Obama locked up his party's presidential nomination with a parting shot from some Hillary Clinton supporters, a third of whom in South Dakota and Montana alike said they won't support him in November.

Majorities say they'd be satisfied with either Democratic candidate as the party nominee, as Obama faces challenges uniting his party in the general election.

(ABC News Photo Illustration)

But that's fewer than have said so in other recent primaries.

The Struggle for Unity

These and other exit poll results underscored the challenges facing Obama as he seeks to unify the party.

About half of Clinton's supporters in both states said they're dissatisfied with him as the nominee, said he doesn't share their values and didn't see him as honest and trustworthy.

In the six previous primaries, however, more Clinton supporters -- 47 percent -- have said they wouldn't vote for Obama, and more doubted that he shares their values and questioned his honesty.

It's an open question whether the polarization moderated or the final two states just were different.

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The Note

In either case these are criticisms expressed by Clinton voters in the heat of battle; whether they linger remains to be seen -- but they suggest that the way Clinton leaves the race does matter, now that Obama has claimed enough delegates to secure the Democratic nomination.

In both states, satisfaction with Obama as the nominee, ratings of him as honest and trustworthy and the view that he shares Democratic voters' values all were much higher, naturally, when his supporters are included.

And even as he lost South Dakota, voters there narrowly picked Obama as most likely to win in November; in Montana, where he won, voters by a wider margin called him more electable than Clinton.

South Dakota, Montana Follow Similar Patterns

Voting patterns in these contests reflected the divisions that have been customary during the campaign: Clinton did better among seniors, less-educated and lower-income voters and mainline Democrats; Obama prevailed by a wide margin among voters under 30 and did better with more-educated, better-off and independent voters.

Turnout among these groups helped explain the outcomes: Mainline Democrats accounted for only about 60 percent of voters in Montana's open primary, vs. more than 80 percent in South Dakota's closed contest; and college graduates were more prevalent in Montana by roughly a 10-point margin.