I think he’s burned too many bridges in the Senate to be effective. Consider that he is universally disliked there and not a single senator has endorsed him. NONE. His best hope in future is to get cabinet role or Supreme Court spot in next Republican administration. Else, run for a house seat since he seems to enjoy playing politics there as much or more than in the senate.
This is a straw mans argument.
Politics has no memory when dealing with positions of power.
You honestly think previous disagreements do not reset once Cruz is elected President?
Additionally, you seem to think Trump is above taking money. If he gets the nomination, he’ll get plenty dirty with “filthy donor money” during the general.
By the way, Cruz’s donors are mostly small grassroots style donations... I guess money from the average joe is bad in your opinion?