"It is utterly hypocritical for Congress to extol the virtues of a colorblind society while officially sanctioning caucuses that are based solely on race," said the Colorado Republican, who is most widely known as a vocal critic of illegal immigration.
"If we are serious about achieving the goal of a colorblind society, Congress should lead by example and end these divisive, race-based caucuses," said Tancredo, who is scheduled pitch his longshot presidential bid this weekend in New Hampshire.
Tancredo's request, relayed in a letter to Administration Committee Chairwoman Juanita Millender-McDonald, D-Calif., revived his effort to change House rules to abolish the groups. Besides the Congressional Black Caucus, Democrats also have a Hispanic caucus with 21 members, and Republicans have a comparable Hispanic conference with five full members and 11 "associate" members who are not Hispanic.
The request comes in the wake of reports that freshman Rep. Stephen Cohen, D-Tenn., was refused admission to the Congressional Black Caucus because he is white. All 43 members of the caucus are black.
Cohen said in a statement that he told a reporter that he would be honored to join the caucus but did not apply, "nor has the CBC denied membership to me."
The political Web site Politico.com, which first reported the issue, quoted Rep. William Clay, Jr., D-Mo., as saying the black membership in his group is "an unwritten rule."
Tancredo is chairman of the Congressional Immigration Reform Caucus, which seeks to toughen border security to stem illegal immigration from Mexico. He also opposes guest worker programs and immigration proposals by President Bush, saying they would facilitate more foreigners coming to the United States illegally.
He won re-election in November from voters in his south-Denver district with 59 percent of the vote.