Obama and McCain's back and forth may be helping McCain.

WASHINGTON (CNN) – A new national poll suggests the increased bickering between Sens. Hillary Clinton and Barack Obama could affect Democratic turnout in November.

Sixteen percent of Clinton supporters questioned in a CNN/Opinion Research Corporation survey released Thursday afternoon said they are not likely to vote in the general election if Obama is the Democratic nominee. An equal number of Obama supporters said they'll sit it out come November if Clinton is their party's nominee.

"The problem for the Democratic Party in November may not be crossover votes — Clinton supporters choosing McCain in the fall if Obama wins the nomination, or Obama voters doing likewise if Clinton gets the nod," said CNN Polling Director Keating Holland. "The real problem may be that those disaffected Clinton or Obama supporters may just stay at home in November, which could cost the party dearly in some key states.

"If the Obama stay-at-home vote is largely African-American, that will affect Democrats' chances on the ballot in several Southern states, and could take states like Virginia off the table completely," he said. "It might even hurt Democrats in states where the party relies on heavy turnout in large urban areas, such as Pennsylvania and Ohio. And if the Clinton stay-at-home vote is predominantly female, that will hurt the party everywhere."

It should be noted, however, that polls are a snapshot of how people feel at the moment. If the Democrats can come together and agree on a nominee, most of the ill-will could be just a memory by November.

But a look back in history shows primary animosity has carried over into the general election before.

In 1980, the nomination fight between Jimmy Carter and Ted Kennedy lasted all the way to the convention. The result was a drop in the number of liberals who voted in the fall.

In 1992, Pat Buchanan staged a conservative challenge to the first George Bush that left many of his followers angry at the incumbent. The result was a drop in the number of conservatives who came out to vote in the general election.

Both Carter and Bush lost those elections.

The CNN/Opinion Research Corporation poll was conducted by telephone from Friday through Sunday, with 1,019 Americans questioned, including 227 registered Democrats who said they support Hillary Clinton and 218 registered Democrats who said they back Barack Obama. The survey's sampling error is plus or minus 5.5 percentage points.