Interesting info, and the part where both sides defect on near unanimous bills matches what I've seen as well (think the annual defense bill). One thing I notice about the examples you give is that they're not the votes everyone is watching and the media reports on, like signature legislation, Supreme Court nominees, and impeachment votes. I was surprised to find out that 5 House Democrats supported the Clinton impeachment, although most of those were conservative Democrats who later become Republicans.
Interesting info, and the part where both sides defect on near unanimous bills matches what I've seen as well (think the annual defense bill). One thing I notice about the examples you give is that they're not the votes everyone is watching and the media reports on, like signature legislation, Supreme Court nominees, and impeachment votes. I was surprised to find out that 5 House Democrats supported the Clinton impeachment, although most of those were conservative Democrats who later become Republicans.