The vast Internet spaces known as political Web logs, where anyone can post an opinion, are attracting some virulent political snipes, leading candidates to call on their opponents to distance themselves or risk being accused of sharing the same thoughts.

Last week, for instance, Joe Lieberman called on his Democratic primary opponent, Ned Lamont, to denounce one of his supporters who posted on the HuffingtonPost a doctored picture of the Connecticut senator in blackface.

Accusations have been made about Montana U.S. Senate candidate Jon Tester's leanings because of support he received on the DailyKos site, which also has postings in support of Cuban dictator Fidel Castro; and Democrat Bob Casey has been linked to an anti-Semitic Web log after a blogger on the site threw his support to the Pennsylvania candidate for U.S. Senate.

A blog includes personal opinions and reflections posted on a Web site and usually offers readers the ability to comment on posted material. Anyone can add their opinion, regardless of how nutty or obnoxious it is.

“Anybody and everybody can participate. It’s a big free-for-all,” said Carol Darr, director of the Institute for Politics, Democracy and the Internet at George Washington University.

Blogs are popular, according to surveys by the Pew Internet and American Life Project, with about 12 million Americans or 8 percent of adult Internet users participating in them. While the largest plurality of bloggers, 37 percent, write about life and experiences, about 11 percent of posts are about politics and government, according to the survey.

Political blogs began to surface a few years ago, with their impact really being felt during the 2004 presidential election season. People who visit political blogs are generally political junkies with big social networks, Darr said.

"They have an influence that is disproportionate to their size," Darr said. “I think they are a force to stay."

In recent weeks, as the 2006 midterm election season heats up, some back-and-forth bickering has flitted across the blogs and as a result, the campaigns.

In the Montana U.S. Senate race, pundits took notice when Tester, a Democrat running to unseat Republican Sen. Conrad Burns, linked the DailyKos blog to his election Web site. The National Republican Senatorial Committee blasted the link, calling DailyKos, among the most popular Democratic blogging sites, and its editor Markos Moulitsas “ultra-liberal” and "hateful."

“By linking to Kos’ blog from his own site and using it to raise money, Tester encourages this extreme rhetoric,” said NRSC spokesman Brian Walton. “Jon Tester should remove the link to DailyKos from his site and repudiate Kos’ hate-filled politics.”

Tester's campaign said the NRSC is trying to divert attention away from the race.

"The only criticism we've heard is from the NRSC, who are grasping at straws and will try anything to change the subject from Sen. Burns' record," said Matt McKenna, a spokesman for Tester.

Tester’s campaign Web site posts links to 17 blogs, including DailyKos. Tester has his own blog on the site, too.

"The Tester campaign understands that blogging is a conversational medium, and so we provide links to other blogs that are talking about the 2006 race in Montana," McKenna said. "But we don't monitor what other blogs say. It's simply a resource to point our visitors to other blogs that may be of interest to voters."

The Lieberman-Lamont race that was decided this week had already been one of the most-watched contests of the year before blogger Jane Hamsher, a Lamont supporter, posted a fake photo of Lieberman in blackface alongside former President Clinton.

The picture launched debate across the blogosphere and angered the Connecticut senator. Lieberman called on the multi-millionaire cable company executive to disavow Hamsher, who is not a paid staffer on his campaign, but promotes the now-Democratic Senate nominee on her own blog Firedoglake.

Asked whether he would persuade Hamsher to withdraw the photo, Lamont said, "I don't know anything about the blogs. I'm not responsible for those. I have no comment on them." However, Hamsher, whose blog is linked from Lamont's campaign Web site, said she pulled the photo at the request of the candidate.

The race for Senate in Pennsylvania also got heated over the Al-Jazeerah Web site throwing its support behind Democrat Bob Casey in an editorial that slammed Republican Sen. Rick Santorum for calling for regime change in Iran and describing "Islamic fascism" as the greatest test of the generation.

The site, based in Georgia and unrelated to the Arabic television network Al-Jazeera, carries photos with captions that describe "Israeli terrorist raids" on Beirut, refers to Hamas founder Sheik Ahmed Yassin as a martyr and accuses the U.S. Senate of being controlled by the American-Israeli Political Action Committee.

Santorum made light of the editorial to reporters, but while doing so made the mistake of thinking it was the site owned by the Arab network. For that, he was excoriated on Democratic blogs.

"What a story. I love starting my week off with idiot republican morons pulling off more stupid stunts for their gains," wrote an individual identified as Bleuto on the HuffingtonPost.

But another writer appearing on the democraticunderground discussion board said Democrats might not want to make so much fun of the error.

"Santorum's flub is amusing, but the actual site is probably one that Casey doesn't want to be too closely tied to, either. Of course, the underlying silliness is that all major candidates collect some support from people they'd just as soon keep at a distance," wrote a poster named Jim Lane.

While it is a hard charge to try to link individual writers to the campaigns, some power has slipped away from traditional decision-making organizations, giving blogs an edge, said Robert Cox, president of Media Bloggers Association, a nonpartisan organization that supports blogging as a form of media and defends bloggers' rights.

"Blogging has certainly enabled a whole new set of groups of people to come in and compete for attention in the national dialogue on political issues," Cox said.

Chris Nolan, editor and founder of spot-on.com, said the medium is a powerful way for political consultants to operate online.

"What they are replacing is good, old-fashioned op-ed research," Nolan said. "It's a symptom of how mediocre much of the political reporting being done in this country really is."

Blogs are no different than a TV advertisement, direct mail or other campaign-type effort to push an issue or candidate, said Nolan, whose site uses blogging software to post objective reporting on the Internet.

But Democracy for America Executive Director Tom Hughes said bloggers are not the go-to source for campaigns seeking an edge.

"Blogs are a new battlefield for campaigns, but they don’t replace television, radio or knocking on doors," Hughes said.

Still, the Internet, and specifically the political activists that can be found on Web logs are not going unnoticed. Senate Minority Leader Harry Reid and other Democratic leaders asked for support from bloggers attending the YearlyKos convention held in Las Vegas in June. Many Democratic candidates and the Democratic National Committee host blogs as do their Republican counterparts.

Linking candidates to specific bloggers may not always work, but the types of blogs that support candidates should speak volumes for voters, said Santorum campaign spokeswoman Virginia Davis.

"These are the kinds of people that are supporting Bob Casey for his wishy-washy, unclear positions on our nation's security and that should be very troubling for Pennsylvanians," Davis said.

"Clearly this person who’s tied to radical Islam believes that Bob Casey is the better choice for the U.S. Senate, because Bob Casey is weak on national security and foreign policy issues. Casey’s foggy comments about the war in Iraq and foreign policy, in general, are of great concern to Pennsylvanians, but are exactly what those who oppose our efforts to address this threat want to hear," she said.