The Commission on Presidential Debates announced yesterday that participation in this year's general election debates will require candidates to have at least 15 percent support in national polls.

The new ground rule will make it much more difficult for anyone but the Democratic and Republican nominees to take part in the nationally televised events this fall.

In addition, the candidates must meet the constitutional requirements to be president and must appear on enough state ballots to have a mathematical chance of winning.

Reform Party candidate Patrick J. Buchanan reacted angrily. "The Commission on Presidential Debates's decision to limit access to candidates who pass a high threshold of poll support--a threshold set by the dominant parties--is a transparent farce," he said. "This is nothing but a Beltway conspiracy by the two establishment parties to corner the market forever on the presidency of the United States."

Buchanan, who abandoned the GOP last year, has said that he must participate in the general election debates to be competitive. Buchanan, however, has been mired in single digits in most national polls.

"It's a real Catch-22," said Gary Sinawski, a New York lawyer who has represented Lenora Fulani, a perennial third-party candidate. "Being in the debates is what gets you to 15 percent. Look at Jesse Ventura," the Reform Party governor of Minnesota.

As specified by the commission, potential debate participants must garner at least 15 percent support approximately a week before each debate, based on an average from the polls of the following news organizations: Washington Post-ABC News, New York Times-CBS News, Wall Street Journal-NBC News, USA Today-CNN and Fox News-Opinion Dynamics.

Commission co-chairman Paul G. Kirk Jr. said he hopes the new standards will avert a recurrence of the controversy that arose over the commission's decision to exclude Reform Party nominee Ross Perot in 1996 after it had allowed him to participate as an independent in 1992.

"We have applied our criteria for the past three cycles, and I will freely admit that sometimes the application has been contentious," Kirk said. "We are making this announcement nine months in advance of the debate schedule so that there will be no room for doubt that these [standards] are clear, they are emphatically nonpartisan and they are predictable."

Kirk, a former Democratic National Committee chairman, heads the commission along with former Republican National Committee chairman Frank J. Fahrenkopf Jr.

The commission also announced the dates and sites of the debates: Oct. 3 at the John F. Kennedy Library, University of Massachusetts, Boston; Oct. 11. at Wake Forest University in Winston-Salem, N.C.; and Oct. 17 at Washington University in St. Louis, Mo. The vice presidential debate will be held on Oct. 5 at Centre College in Danville, Ky.