Cruz was assuring himself a lead position for the 2020 Republican nomination after Trump loses the general election in November 2016.
If Trump wins, Cruz would be out of play until at least 2024 and traditionally the sitting VP gets first shot at the nomination, so he could find himself out of the running for 16 years.
I’m hoping Trump loses and Cruz has alienated enough Republicans that they pick another poor candidate in 2020.
I admit my Democrat bias