“can argue the case”
Corrected: “will argue” Cruz has lots of options and he won’t settle for being a perennial limp-d*** senator like McCain or until he’s pastured like Luger.
Corrected: “will argue”
You say it's lack of courage, etc. I say it goes even further. The vast majority of these Congresscriters have long ago lost the mental capacity to make the case for what is right. They are spiritually lost and they need to go.
They didn't spend their formative years touring Texas debating liberty and the constitution, as Cruz did. They are, by and large, Johnny-come-latelies to Conservatism, attracted by a host of other factors like a desire for power, prestige or an amorphous feeling that they could do their civic duty, without ever understand what that really entails.