The formal invitations went out Friday for the presidential debates, and there was no gold-embossed card for independent Ralph Nader (search).

The Commission on Presidential Debates asked President Bush (search) and Democratic Sen. John Kerry (search) to meet for their first debate next week. The commission also invited Vice President Dick Cheney and Sen. John Edwards to a single debate on Oct. 5.

Invitations were based on nonpartisan selection criteria adopted last year: that participants be constitutionally eligible for election; that their names appear on enough state ballots to have a mathematical chance of winning enough electoral votes for election; and that they receive at least 15 percent in an average of five national polls to show support for election.

In a statement, the commission said no other candidates besides Bush and Kerry met all the criteria.

Most national polls show Nader receiving only 1 percent to 2 percent support. Even that number may be inflated, however, because Nader has not qualified for the ballot in at least a dozen states, including California, Illinois, Missouri and Virginia. Nader is currently on the ballot in about 30 states.

The first presidential debate will be Thursday at the University of Miami in Coral Gables, Fla. The second, a town-hall style format, will be Oct. 8 at Washington University in St. Louis, and the third will beheld Oct. 13 at Arizona State University in Tempe.

One vice presidential debate will take place Oct. 5 at Case Western Reserve University in Cleveland. All debates will be 90 minutes in length and begin at 9 p.m. EDT.

The commission is a nonprofit and nonpartisan corporation established in 1987 to sponsor and produce presidential debates. It has sponsored all the presidential debates since 1988.