The Federal Election Commission has begun considering whether to issue new rules on how political campaigns are waged on the Internet, a regulatory process that is expected to take months to complete but that is already generating considerable angst online.

The agency is weighing whether -- and how -- to impose restrictions on a host of online activities, including campaign advertising and politically oriented blogs.

Election officials are reluctantly taking up the issue, after losing a court case last fall. The FEC, which enforces federal election law, had issued scores of regulations delineating how the campaign finance reform legislation adopted in 2002 ought to be implemented. But Reps. Christopher Shays (R-Conn.) and Martin T. Meehan (D-Mass.), who sponsored the legislation, complained that many of those rules were too lax, and they successfully sued to have them rescinded. The commission must now rewrite a number of those directions, including ones that left online political activities virtually free from government regulation.

"We are almost certainly going to move from an environment in which the Internet was per se not regulated to where it is going to be regulated in some part," said FEC Commissioner David M. Mason, a Republican. "That shift has huge significance because it means that people who are conducting political activity on the Internet are suddenly going to have to worry about or at least be conscious of certain legal distinctions and lines they didn't used to have to worry about."

Which people, what activities and where those lines should be drawn, though, have yet to be determined. The rise of the Internet as a political tool, the variety of ways in which it can be used to promote a campaign and the fact that most federal election laws were written long before the Internet became a household word have combined to present the agency's commissioners with plenty of knotty legal questions to consider.

Should bloggers who work for political campaigns, for example, be required to disclose that relationship? Should their writings include a disclaimer indicating that they were paid for by a campaign? What if a campaign supporter links his Web site to a candidate's home page? Is that considered a campaign contribution subject to government regulation? What if an independent blogger endorses a candidate? Or posts a campaign's news release? Are those contributions?

The panel, which has been criticized for being slow to decide contested points of the law -- but is loath to do anything that would chill free speech -- is free to address whatever issues it chooses. The three Democrats and three Republicans who compose the commission have not settled on an agenda for this latest round of rulemaking. That is expected to come later this month. But several commissioners have begun making their suggestions public.

Republican Commissioner Bradley A. Smith, who opposed some previous attempts to impose regulations on online political activities, sparked a furious debate among bloggers earlier this month, when he told the online technology magazine CNET that the FEC might regulate their activities. He argued, for example, that the laws that allow publications such as this newspaper to make political endorsements without having them considered akin to financial contributions to those campaigns -- and therefore subject to government regulation -- may not apply to bloggers who back candidates.

His comments quickly ricocheted across the Web, as bloggers began wondering if they might have to bone up on election law. Two of the authors of the campaign finance legislation, Sens. John McCain (R-Ariz.) and Russell Feingold (D-Wis.) issued a joint statement denouncing Smith's remarks, saying they would "whip up baseless fears." A few prominent online political strategists and bloggers sent a letter recently to the FEC, urging it not to restrict unpaid political activities on the Internet. Their letter has since been endorsed by more than 2,500 other supporters. Republican Commissioner Michael E. Toner said he has begun receiving "very heated" e-mails on the issue.

Four commissioners -- Democrats Scott E. Thomas and Ellen L. Weintraub, along with Toner and Mason -- said in interviews that they oppose regulating independent bloggers.

"I really see no appetite at the agency for regulating bloggers," Weintraub said. "I would be very, very surprised if that was the result."

She said the commission would likely focus on other issues, such as whether to subject expenditures on Internet ad campaigns to the agency's contribution rules. The FEC requires campaign supporters who spend money on political ads in coordination with a candidate to report those expenses to the government and subjects them to contribution limits -- but the rules apply only to offline ads. So if, for example, a campaign supporter pays for an ad in the Los Angeles Times at the request of a candidate, that expenditure must be reported and counted against those limits. But if the supporter pays for an ad on the Los Angeles Times's Web site, it does not.

Weintraub also predicted that many of the activities mentioned as possible items on the FEC's agenda would ultimately fall outside its jurisdiction.

"We regulate campaign finance. We don't regulate speech in the abstract. We only regulate when money is spent," she said. "One of the great things about the Internet is that it's really cheap, and if people are not spending money, then it's really none of our business. Most of the time when people are sitting at their home computers, blogging, e-mailing -- whatever they're doing -- there really isn't any money being spent."

Some longtime FEC observers said they believed the commission would tackle a relatively narrow slate of issues.

"I don't think this is going to be as broad a rulemaking as some are threatening," said Larry Noble, a former FEC general counsel who now runs the watchdog group Center for Responsive Politics. "I think what the FEC is going to focus on is political activity undertaken by campaigns, by political committees, by possibly corporations and labor unions on the Internet . . . how you regulate that, how you make sure that's reported."

The commission is not expected to reveal its agenda until later this month, when it releases its "notice of proposed rulemaking." The FEC is scheduled to then invite public comments on that draft, hold a public hearing on the proposed rules and, later this summer, vote on the final regulations.