Yes, but it is the criticality of the vote. His Obamacare stances just now are meaningless, whereas the Obamatrade vote has the potentiality of complete destruction of the United States as a sovereign nation, literally, without exaggeration. Also he complied with the Obama agenda when he voted to allow Iran to develop atomic weapons. Of course, the bill doesn’t stipulate that, just as the Obamatrade does not stipulate its end game.
And your better candidate is .....
Regarding fast track authority, there is a legitimate argument that can be made that Presidents need to be able to negotiate in good faith with other countries without the threat of Congress holding up and changing the negotiations midstream. I don't know if I fully agree with that argument but it can legitimately be made. This is especially true if he thinks he might be President someday and have a Congress that is controlled by the Dems.
I don't know this answer and I would be curious to find out....Has a Democrat controlled congress ever given a Republican president fast track authority on a trade bill or a treaty such as they are working on with Iran?