that could be an interesting question. Both the nominee and President could probably do so. I think that any Senator would have standing since it affects his right to vote on the candidate (but I seriously doubt any Senator would dos so considering the political consequences); by extension, any voter might be able to make a case for having standing to sue since it is directly affecting his Senators ability to vote (although a problem might arise with the Senators representing the States and not the individual voters). From a purely research standpoint, I find the standing to sue to be more interesting than the case itself (finding a way to give every voter a standing to directly sue the Congress for either action or inaction would be interesting). BTW, are you familiar with validating the results of your case research (Shepardizing)?