At any rate, the early prognostication is that his chances are somewhere between slim and none.
What are Cruz's prospects for winning the GOP nomination in 2016, and then the presidency? They are absolutely terrible.Well, it's a two-part question. First, on the general election: yes, Cruz is likely to be perceived as an ideological outlier, but that's a penalty, not a disqualification -- it didn't, for example, prevent Ronald Reagan from winning. I'd guess that Cruz probably spots the Democrats two or three percentage points compared with someone with a more moderate image -- which matters, but is hardly the end of the story.
As a candidate for the nomination, the basics are that Cruz would be a minimally viable candidate: he will have conventional qualifications, if slightly on the skimpy side, and is probably more or less within the ideological mainstream of his party -- most of his dissent within the party appears to be more about attitude than issues, and if immigration winds up being his big issue he may well be more inside the mainstream than his opponents.
Will it matter that Republican Senators (reportedly) don't like him? It's not a plus -- Barack Obama, with similar conventional credentials, was surely helped within the party because Democratic Senate leaders vouched for him. On the other hand, Members of Congress are traditionally overrated within presidential politics. As for his general McCarthyite tactics, that's probably more of a plus than a minus among Republican activists, and perhaps even other Republican party actors.
That doesn't mean, of course, that Cruz is likely to win; it's far too long from now to then to really have a good sense of it. He is, for now, just another candidate. And, as with all viable nomination candidates, he'll have strengths and weaknesses that are revealed through the long campaign. But as far as I can see (and assuming that he's actually eligible for the office), there's no obvious reason to believe that he has no chance.
And pretty much anyone who could win a major party nomination has a reasonable chance of winning the presidency.
*My apologies for getting this wrong. Updated and corrected as indicated.