Rep. Bobby Rush of Illinois points out that Roland Burris would be the only black man in a chamber populated overwhelmingly by white senators.
Senate Democratic leaders earlier Tuesday added an explicit note of support for Burris personally, but not for his appointment by the embattled governor of Illinois, Rod Blagojevich. The leaders said the Democratic caucus would refuse to seat Burris if Blagojevich appoints him, and called their stance a reflection of the scandal-tainted governor.
Blagojevich denies charges that he tried to sell Obama's Senate seat for personal gain.
The 71-year-old Burris is a former Illinois attorney general.