The Tea Party is off.

At least, the National Tea Party Unity Convention that was being planned for mid-October in Las Vegas is off. It was supposed to be a repeat of the convention in Nashville last February, which drew 600 “delegates” (and almost as many reporters) and an adoring audience for Sarah Palin, the keynote speaker.

Sponsored by Tea Party Nation, a social networking site, the convention was supposed to emphasize Tea Party groups working together — a contrast to the convention in February, which was plagued by infighting among groups, with sponsors and speakers dropping out right up until its opening hours. Organizers chose Las Vegas not least because it is the center of the Senate race that Tea Party activists would most dearly love to win: Sharron Angle, a Republican supported by Tea Party groups, is challenging Harry Reid, the leader of the Democratic majority.

Barbee Kinnison, a Tea Party activist in Las Vegas who had been helping organize the convention, sent an e-mail to supporters saying that it was with “deep sorrow” that she had to announce “the convention is just not going to happen.”

Tea Party Nation still draws scorn from some other Tea Party groups, which have raised eyebrows at asking people to spend more than $200 to attend a convention, so it was not clear what this said about the strength of the movement. Tea Party Patriots, a large umbrella for about 2,700 local Tea Party groups nationwide, had criticized the media attention on the convention in February, saying it was not a real representation of Tea Party activism.

But Ms. Kinnison said in her e-mail that “the various large ‘other’ Tea Party organizations have slid in their participations and donations across the country, and their events are free.”

A group called Unite in Action had hoped to have a three-day Tea Party extravaganza of seminars and rallies in Washington starting Sept. 10, but Ms. Kinnison said that classrooms that the group had set up for 500 people ended up with only 5 in them. And a rally held by FreedomWorks that Sunday, while large, was far smaller than the one the group held a year ago.

“This was to be our gauge for the convention and if the owners should pursue the convention and see if they could even break even,” Ms. Kinnison wrote. “Well, the reports back from Washington were not good. The bottom line is … no convention this year for Tea Party Nation!”

She urged that this not be an end to activism. “The anger should be boiling now,” she wrote, adding: “When November rolls around, I am begging everyone I can to vote! We are the only ones who know what the real world is like. Let’s put this pompous and impervious collection of Congressional men and women out of work!”

The convention had already been postponed once, in July. Organizers said then that the midsummer heat in Las Vegas was making it hard to sell tickets.