That's the argument of David Brooks according to this piece in the New Republic by Scott Lemieux.
Brooks has a story about the fight over the Republican presidential nomination that has become a common one. Trump has no longstanding commitment to the Republican Party; does not even make a pretense of knowing anything about policy; breaks from party orthodoxy on issues like trade; mobilizes racial and ethnic resentment in a way that is too loud and overt for elite Republicans; and is thus unacceptable. But Ted Cruz’s straightforwardly radical conservatism isn’t acceptable either:
If the G.O.P. is going to survive as a decent and viable national party, it can’t cling to the fading orthodoxy Cruz represents. But it can’t shift to ugly Trumpian nationalism, either. It has to find a third alternative: limited but energetic use of government to expand mobility and widen openness and opportunity. That is what Kasich, Rubio, Paul Ryan, and others are stumbling toward.
Brooks’s narrative ... founders on one problem: Substantively, there’s not a dime’s worth of difference between Cruz and alleged moderates like Kasich, Rubio, and Ryan. And none of them have policy agendas that are any more serious than Trump’s.
Lemieux then proceeds to rip those supposed moderates' policies to shreds.
The alternatives to Trump and Cruz that Brooks touts, in other words, fully reflect the Republican orthodoxy that turned Trump and Cruz into frontrunners. Like Cruz, they’re all committed to radical and unpopular fiscal plans that, in a time of increasing inequality and economic insecurity, would gut cherished programs for the poor and the middle class to pay for a huge redistribution of wealth to the top 10 percent. Like Trump, they’re also completely unserious about policy, making ridiculous claims about the economic magic of tax cuts that have left the finances of states like Louisiana and Kansas in utter ruins. They are barely even pretending to offer an alternative to the 20 million people they want to deprive of health insurance. (Trump’s health care “plan” is essentially cut-and-pasted from the non-plans of his allegedly more serious rivals.) And for good measure, they’re all climate-change deniers.
Whatever relationship they have to their party elites, Cruz and Trump are perfect symbols of what the Republican Party has become, however much Brooks and the establishment might prefer to pretend otherwise.
Brooks and the other observers really do need to read up on the Authoritarian movement. Republicans are not "stumbling toward" one of the supposed moderates. America is stumbling toward a 3-party system.