An attorney for Burris, Timothy W. Wright III, said that "our credentials were rejected by the secretary of the Senate. We were not allowed to be placed in the record book. We were not allowed to proceed to the floor for purposes of taking oath. All of which we think was improperly done and is against the law of this land. We will consider our options and we will certainly let you know what our decisions will be soon thereafter."

Asked what his options were, Wright said there could be a court challenge and Burris also would continue to talk to Senate leaders.

Some of Burris' supporters have bemoaned the fact that Democrats would stand in the way of the Senate gaining its only black member. Burris himself downplayed the issue of race, telling reporters: "I cannot control my supporters. I have never in my life, in all my years of being elected to office, thought anything about race."

"I'm presenting myself as the legally appointed senator from the state of Illinois. It is my hope and prayer that they recognize that the appointment is legal," he said earlier on CBS' "The Early Show."

Members of the Congressional Black Caucus said Tuesday that Burris should be seated.

"A lot of people want to talk about race or the governor and his problems, but the bottom line is you have a sitting governor who has certain legal rights and authorities and he's made an appointment," said Rep. Elijah Cummings, D-Md. "This is an issue that goes beyond race."