2008: 'Dirtiest Presidential Campaign in History'

Some political experts say the 2008 campaign is already showing its ugly side.

ByABC News
January 3, 2008, 1:36 PM

Jan, 3, 2008— -- Iowa Democrats received a new round of anonymous phone calls this week, under the guise of opinion poll research, slamming former Sen. John Edwards and Sen. Barack Obama, in the latest display of the ugly side of this year's presidential campaign.

Even before the first vote is cast, 2008 is being called "one of the dirtiest campaigns in American history" by a political science professor who is tracking campaign dirty tricks and opposition research attacks on rival candidates.

"When you're spending this much money, and there's this much at stake, you're going to have dirty tricks played," says Larry Sabato, director of the Center for Politics at the University of Virginia, in an interview for a "20/20" report.

Watch the "20/20" Report.

The negative phone calls are known by experts as push poll calls because they push negative information.

"Some foreign policy experts say that John Edwards' plan to pull out all combat troops in Iraq within the next 10 months is irresponsible," says the questioner. "Does this statement influence your feeling about John Edwards a lot, somewhat, not too much, or not at all?"

On Obama, the caller says, "Barack Obama has taken millions of dollars from big banking and energy interests that have legislation before the Senate. Does this influence your feeling about Barack Obama a lot, somewhat, not too much, or not at all?"

Listen to part of the call here.

The caller said the calls were coming from an "independent research firm." The caller ID showed no return number, only 000-000-0000.

The call made no reference to Sen. Hillary Clinton, whose campaign spokesman "categorically denied" it had any connection to the Clinton campaign.