Senator Tom Harkin says there should be four, not just two, candidates in tonight’s presidential debate. Republican George W. Bush and democrat Al Gore face-off tonight in a nationally broadcast debate. Harkin says Green party presidential candidate Ralph Nader and Reform party candidate Pat Buchanan have legitimate complaints about being left out.Harkin says the American people would be better served if all four candidates were able to debate one another in a nationally televised forum.The Bi-partisan Commission on Debates restricts participation to candidates who have at least 15 percent support in public opinion polls. For example, independent candidate Ross Perot participated in the 1992 debates with George Bush and Bill Clinton. Harkin says this time around, Pat Buchanan has the best argument for being included in the debates, as Buchanan qualified for federal matching funds.Harkin made his comments in Wisconsin as he campaigned on Al Gore’s behalf. Harkin ran for president in 1992 — but dropped out of the race early.