Reid doesn’t, but my understanding is that the Senate, as a body, can decline to seat anyone either appointed or elected.
You are correct the Houses of Congress have sole authority over who is allowed to fill Senatorial and Congressional seats. They may expell with a 2/3s vote.
See Article I, Section 5, paragraphs 1-2 in the Constitution.
Do you think the Senate could refuse to certify one Barack Obama, in their capacity of determining the Constitutional eligiblity of a candidate to be President— that is, the individual MUST be a natural born citizen of the United States. The law requires this legal duty. Maybe Cheney can say -— wait a minute, I object. This would occur on Jan. 8th.