That strikes me as the same type argument that the Democrats used in 2004: "We're not George Bush". The recent cloture vote on gave me at least seven reasons to not support generic Republicans and ten possible reasons to like the Democrats. Of course, one might argue that some of the Democrat votes were for other reasons, but I think Boxer knows that her constituents will really be upset if amnesty carries. Maybe "Sheets" Byrd is just a bigot. That still leaves eight good Democrats.
In case you missed the link above, here are the Republicans who favor amnesty:
Here are the Democrats who helped keep the amendment from coming to a vote:
Call or write and thank them.