Fundamentals of narcissism must be understood to properly analyze anything Mr Trump does. One must view everything he does through the lens of his delusional world, in which he is the greatest (he knows more than anyone alive). However, don't be confused and overthink his actions.
His actions while dictated by his view of himself are not exclusive nor inclusive of any singular political ideal. Examples would be appointing ultra conservative people to courts, rescinding regulations which impact fundamentalist Christians, signing conservative agenda bills, etc. On the other hand he endorses political ideals which run counter to conservative orthodoxy, like trade.
KISS ... if one tries to comprehend his actions as a reflection of a cohesive cogent agenda, one ends up scratching their heads in confusion. However, viewed through the lens of his own self interest, the smoke clears up and reveals what lies at the heart of his agenda, actions dictated by his delusional world.
Those Republican Senators peeling off from him are the same ones that might just impeach him
And here is where I will disagree.
While it is true these Senators will be the ones, who, if impeachment ever makes it to the floor of the Senate, would be the jurors, I think we are talking about two disparate concepts. There may be enough Republican Senators to support a rational ending to the shutdown, and in fact may be enough to overcome a veto (it would actually do no good if there were not enough Republicans to do that). however, I do not believe that translates into votes for impeachment conviction. All I think it means is there is a difference in politics, not necessarily in support of agendas.