District of Columbia code 3501 has been used in the past to remove senators that were not qualified by lack of citizenship. obama falls under the same rules. if is proven that his father was not an American citizen, congress can void his election. Of course, first you ned acopy of his birth records( certified,court legal).
I don’t think that your legal reference is accurate. After a Senator takes office there is nothing which can remove him during the term except the action of the Senate itself. Certainly no District of Columbia code (nor state laws, either) has ANY control over the federal government .
Nor is there anything in the Constitution that the Congress has any power to void an election per se. Each house can remove a sitting member or refuse to accept a newly elected one. After it has accepted the electoral college’s vote for President and VP it cannot nullify the election except through impeachment.