Only top three invited to be at Tuesday’s debate

When Las Vegas and CNN played host to a Democratic presidential debate in November, seven candidates were on stage to participate.

At the Cashman Center Tuesday, that number will be three for a debate hosted by MSNBC.

Sens. Hillary Clinton and Barack Obama, the two leading in the polls, will be joined by John Edwards, a former North Carolina senator.

Lackluster performances in the Iowa caucuses and New Hampshire primary are responsible for much of the attrition.

Sens. Joe Biden and Christopher Dodd, along with New Mexico Gov. Bill Richardson, dropped out the race after they were unable to win one delegate among them.

Though Congressman Dennis Kucinich and former Sen. Mike Gravel have remained in the race despite equally dismal results, MSNBC did not ask them to participate in the debate.

Candidates must have attracted a "double-digit" percentage of the votes in Iowa and New Hampshire in order to participate, according to Jeremy Gaines, a network spokesman. "This is now our criteria," Gaines said.

He said that criteria had been established after Richardson dropped out Thursday. Richardson's support was at 2 percent in Iowa and 5 percent in New Hampshire.

Kucinich spokesman David Bright said Friday that MSNBC had earlier sent Kucinich a letter indicating he was invited to the debate.

Kucinich received 1 percent of the vote in New Hampshire. Gravel did not crack 1 percent.

By not allowing Kucinich to participate, MSNBC "was not doing its civic duty," according to Bright. "Vote percentages should have nothing to do with who debates."

Kucinich recently was barred from participation in an ABC presidential debate as well. Gravel, who has had difficultly meeting either fundraising or voter participation criteria set up by networks, has long been barred from debate participation.

"NBC Nightly News" anchor Brian Williams will moderate the debate, which largely will focus on issues of interest to minority voters.