So which are the Republican who may start standing up to Trump first?

I know they are few and far between. Of course we have McCain and Graham already starting to make noise about Russia but I'm not sure if they are really taken seriously. Corker has grave concerns about repealing the ACA without a plan in place. He has some clout in this. Who else can we focus in on sending information and support to on these issues that could be open to influence?

The way I see it we are dependent upon them to help the process in slowing down at least the steamroller that seems to be heading through Congress and the White House.