Democratic Presidential candidate Barack Obama, swept to the role of presumptive nominee through support from fans on the Internet, is learning that the Internet can just as easily be mobilized against him, even after he has already voted on an issue.

The issue is the Foreign Intelligence Surveillance Act, or FISA, a law that explicitly gives President Bush's administration the right to perform certain types of warrantless electronic surveillance that some people had believed was illegal. Obama, while dissatisfied with the final version of the bill, found it an improvement over earlier versions, and without the passage of something, foreign surveillance would have been halted altogether. So in early July, he voted for it, helping pass the bill.

Obama had already telegraphed his intention to vote for the bill, leading net activists to form groups such as "Senator Obama - Please, No Telecom Immunity and Get FISA Right" on Facebook, which currently boasts 2,291 members -- not to mention a group on Obama's own website, My.Barack.Obama, with more than 20,000 members. An issue like warrantless electronic surveillance was tailor-made for the Internet.

But even after he voted for the bill and it passed, Obama supporters who disagreed with him on this issue stayed busy. Now they have a website with more than 200 members, a television ad on YouTube, a discussion forum with 1,032 posts among 169 entries, links to MySpace and Obama's website, and so on. The group said it hopes to get the anti-FISA effort into the Democratic party platform, as well as into Congressional races this fall.

As with Lee Chubb and Sustainable Ketchum, Internet activists have discovered, as described in Clay Shirky's book Here Comes Everybody, how easily Internet technology can be used to set up groups and organize people. The FISA website was literally up the day Obama issued his statement, on July 6.

It shows how a single issue can seize the attention of a large group of people -- and, worse, shift the focus away from the larger prize of working to win the election.