The Bush campaign has said that it never intended to shut down Mr. Exley's site, but merely seeks to see it regulated like any other campaign committee that advocates the election or defeat of a candidate. Last May, the Bush campaign lodged a complaint with the Federal Election Commission against Mr. Exley, charging that he had failed to comply with U.S. election law.

The complaint said Mr. Exley didn't identify himself on his Web site, as the law requires, and noted that if he had spent more than $250 on the site -- the amount at which FEC reporting requirements kick in -- he must also file regular expenditure reports with the agency.

The FEC has taken no action against Mr. Exley, a 30-year-old computer programmer in Boston, whose site continues to operate while the agency reviews the complaint. The Bush campaign also has warned Mr. Exley to stop using copyrighted images from its official campaign Web site.

"If there is any kind of legal move or government move against Zack, we will defend him," said John Whitehead, president of the Rutherford Institute, Charlottesville, Va. He added that Rutherford's main concern was to prevent Mr. Exley from being silenced for political reasons.

Mr. Whitehead likened the Web site's satirical content, which skewers Mr. Bush for everything from alleged youthful indiscretions to his service in the National Guard during the Vietnam War, to political cartoons. "To me, it's kind of repugnant, to be honest with you, that Bush would try to step on this guy," he said.

The Bush campaign has said that Mr. Exley wasn't targeted for the content of his speech. Benjamin L. Ginsberg, the attorney representing Mr. Bush's campaign before the FEC, couldn't be reached for a comment.

Mr. Exley has taken the position that people should be able to publish their political views on the Internet without registering with the government. He said the Bush campaign's actions against him threaten free speech because they send "a message out to everyone else running political sites on the Web," and that he is glad to have Rutherford in his corner.

The FEC has been criticized for attempts to apply election laws, which were written before the advent of the Web, to lone-wolf operators of politically oriented Web sites. While the FEC is unlikely to bring cases against average Internet users, many of whom are oblivious to campaign regulations, critics say the rules give well-funded candidates an excuse to haul lone cybercritics before the agency, exposing them to hefty legal fees, if not sanctions.

In November, the FEC sought comments from the public concerning what rules, if any, should apply to online political activity, including so-called fan sites created by individuals with no ties to a particular campaign. The agency said it will accept comments on such matters until Jan. 4.

While Mr. Exley's Web site began as a satirical effort, he recently began soliciting contributions there for the production of a television and radio advertising campaign critical of Mr. Bush. Mr. Exley says he has raised $7,000 in credit-card pledges so far, but that the money will only be charged to donors' cards when enough funds have been collected to produce and air an ad.