Q: We've now seen three presidential debates between John McCain and Barack Obama. Who decides which candidates are allowed in the debates?

Q: We've now seen three presidential debates between John McCain and Barack Obama. Who decides which candidates are allowed in the debates?

A: In 1976, 1980 and 1984, presidential debates were sponsored and officiated by the League of Women Voters, by all accounts a strictly nonpartisan organization. However, the group withdrew its support before the October 1988 presidential debates, saying that unyielding demands made by the two major parties about how the debates were to be run "would perpetrate a fraud on the American voter."

The Commission on Presidential Debates, a group created in 1987 by chairmen of the Democratic and Republican parties, soon took control. The two-party organization decides when and where the debates happen. It also helps to design their formats. (This year, formats were determined by contracts negotiated among advisers to McCain and Obama and submitted to the commission.)

Most importantly, the commission decides who's invited.

To appear in a debate, candidates must meet three criteria. They must be constitutionally eligible to be president and appear on enough state ballots to have a mathematical chance of winning the election. Finally, candidates must have at least 15 percent support in five selected national opinion polls.

Generally, the most heated discussion surrounds the support benchmark.

"This criterion serves the public interest by striking a fair and appropriate balance between preserving the educational purpose of the debates and providing a healthy chance for the upward movement of new parties and candidates," wrote commission board member Newton Minow in a recent column for U.S. News & World Report.

Minor parties and many voting-rights groups disagree.

Since 1988, only two third-party candidates -- billionaire independent Ross Perot and his running mate James Stockdale in 1992 -- have appeared in nationally televised debates.

Many, including Ralph Nader, running as an independent this year, say the support criterion involves a catch-22: No independent candidate can garner the 15 percent required to enter a nationally televised debate without first being in one.

"Being able to [debate] certainly would've dramatically improved our chances of winning," Libertarian presidential candidate Bob Barr said last week in a phone interview. "Unfortunately, the two major parties have that system rigged. It's impossible to meet their criteria."

Phone calls to the commission and Gallup, the national polling firm that advises it, were not returned.

What's most interesting is that Americans seem to support more open debates.

In 2004, 57 percent of those surveyed in a Zogby International poll said candidates other than George W. Bush and John Kerry should be included in the debates. And, on average, 66.4 million voters tuned in to watch Perot battle George H.W. Bush and Bill Clinton -- the largest audience for any d

If you want a election question answered in this column, e-mail John Ross at jross@columbusalive.com