Ben Domenech, at the Federalist, explains that Cruz’s unexpected move was indeed a calculated and prudential sell-out.
[Cruz’s change of position] came due to those who had been some of Cruzâ€™s most prominent backers. The Mercer family and Peter Thiel played critical roles in elevating Cruz from a virtual unknown in the state of Texas to knocking off a popular Lieutenant Governor in an extremely competitive primary. Now they are prominent backers of Donald Trump, and the threat of a well-backed primary campaign for Cruz in 2018 was increasingly real, with Rep. Michael McCaul and former Gov. and DWTS star Rick Perry showing themselves to be very competitive against him. Cruzâ€™s former media backers had turned on the populist, and the potential for a well-backed challenger against Cruz in Texas was real. Had Trump lost narrowly to Hillary Clinton, as seems the likeliest outcome today, the timing of Cruzâ€™s race wouldâ€™ve made him public enemy number one among the Trump crew.
A move by Ted Cruz to endorse Trump in Cleveland wouldnâ€™t have satisfied anyone already opposed to Cruz, but it wouldâ€™ve seemed like par for the course among all the Republicans whoâ€™ve lined up to back the nominee, which now includes all the candidates this cycle except for Jeb Bush and John Kasich. The move to endorse now seems ideologically baseless, because it is. It seems like an act of political self-defense, because it is. And it seems opportunistic, because it is.