Those who will be at the Jan. 7 session at the University of Oklahoma say that if the likely nominees of the two parties do not pledge to "go beyond tokenism" in building an administration that seeks national consensus, they will be prepared to back Bloomberg or someone else in a third-party campaign for president.

Conveners of the meeting include such prominent Democrats as former senators Sam Nunn (Ga.), Charles S. Robb (Va.) and David L. Boren (Okla.), and former presidential candidate Gary Hart. Republican organizers include Sen. Chuck Hagel (Neb.), former party chairman Bill Brock, former senator John Danforth (Mo.) and former New Jersey governor Christine Todd Whitman.

Boren, who will host the meeting at the university, where he is president, said: "It is not a gathering to urge any one person to run for president or to say there necessarily ought to be an independent option. But if we don't see a refocusing of the campaign on a bipartisan approach, I would feel I would want to encourage an independent candidacy."

The list of acceptances suggests that the group could muster the financial and political firepower to make the threat of such a candidacy real. Others who have indicated that they plan to attend the one-day session include William S. Cohen, a former Republican senator from Maine and defense secretary in the Clinton administration; Alan Dixon, a former Democratic senator from Illinois; Bob Graham, a former Democratic senator from Florida; Jim Leach, a former Republican congressman from Iowa; Susan Eisenhower, a political consultant and granddaughter of former president Dwight D. Eisenhower; David Abshire, president of the Center for the Study of the Presidency; and Edward Perkins, a former U.S. ambassador to the United Nations.

Bloomberg, a former Democrat who was elected mayor of New York as a Republican, left the GOP this past summer to become an independent. While disclaiming any plan to run for president in 2008, he has continued to fuel speculation by traveling widely and speaking out on both domestic and international issues. The mayor, a billionaire many times over, presumably could self-finance even a late-starting candidacy.

"As mayor, he has seen far too often how hyperpartisanship in Washington has gotten in the way of making progress on a host of issues," said Bloomberg's press secretary, Stu Loeser. "He looks forward to sitting down and discussing this with other leaders."

Until plans for this meeting were disclosed, the most concrete public move toward any kind of independent candidacy was by Unity08, a group planning an online nominating convention to pick either an independent candidate or a ticket combining a Republican and a Democrat. The sponsors, an eclectic mix of consultants who have worked for candidates including Jimmy Carter (D) and Sen. Lamar Alexander (R-Tenn.), have not aligned with a specific prospect.

Now, some people with high-level political and governmental credentials are moving to put muscle behind the effort. A letter from Nunn and Boren sent to those attending the Jan. 7 session said that "our political system is, at the least, badly bent and many are concluding that it is broken at a time where America must lead boldly at home and abroad. Partisan polarization is preventing us from uniting to meet the challenges that we must face if we are to prevent further erosion in America's power of leadership and example."

At the session, Boren said, participants will try to draft a statement on such issues as the need to "rebuild and reconfigure our military forces," nuclear proliferation and terrorism, and restoring U.S. credibility in the world.

"Today, we are a house divided," the letter said. "We believe that the next president must be able to call for a unity of effort by choosing the best talent available -- without regard to political party -- to help lead our nation."

Boren said he and Nunn, who often collaborated when they headed the Senate Intelligence and Armed Services committees, respectively, issued invitations to other moderates with whom they had served, and found that almost everyone was willing to come.