I am not 100% sure where Claire's mind is these days.
She seems back on board with her husband, but her callousness toward him at the end of last season and early this season was really reckless for a family so obsessed with public perception.
It crossed my mind that if they are elected and she is VP, she might do something to his meds to ensure she gets to the oval office. I think that when it comes to her sense of purpose in life that she may be unhinged at times.
Most people want to be remembered as having mattered, but she has become pathological about leaving a mark.
It will be interesting to see what the writers do with the first big policy disagreement between the two, and we know it is coming.
I think at the end of season 4, Frank seemed weakened physically, which - - MY WILD IMAGINATION - - could lead to Claire either slowly making sure he gets weaker and weaker, or somehow incapacitating him, yet not killing him. She will then be the acting president, while Frank is lying in a bed somewhere. If there is going to be a Season 6, I can't see it without Frank. However, if next year is the last season, all bets are off as to what lengths Frank or Claire will go to, to get the upper hand on the other.
You have every right in the world to not like Robin Wright or Claire Underwood but to say "Robin Wright is nothing" is just ridiculous. The show needs her as it needs Kevin Spacey -not to mention the many other movies where she gives extraordinary performances-.
Which does happen in Chapter 50 when Frank almost collapses on Air Force One and the doctors order him to cut down on travel to once a week because, as they say, they fear the possibility of an organ rejection.