“There is no doubt about it, that this is the strangest presidential election I’ve covered,’’ said E. J. Dionne, a Washington Post columnist and political commentator. “If any election should make pundits humble, it’s this one.’’

Although both parties have seen surprising primary battles, Dionne said what’s happening on the Republican side is revealing — “we just have not seen anything quite like Trump before.’’ He added that the fight between Trump and Cruz says something about where the Republican Party, and the conservatism at its heart since the mid-1960s, now stands.

In his new book, “Why the Right Went Wrong,’’ Dionne argues that today’s conservative movement is at a crisis point. One problem is ideological — the right these days is “not conservative so much as reactionary,’’ Dionne said. “They want us to go back to an earlier time. I think conservatives are very uneasy with the America that has been created by the cultural changes of the last 50 years.’’

And then there’s the demographic dilemma — how can a political movement survive with such limited appeal beyond older white voters? So far, the GOP has done well with these voters, especially in the midterm elections, Dionne noted. “But if you’re looking out 20 years, you do not want your movement to be based on older voters,’’ he added, “because they are going to pass to their eternal reward, and they will be replaced by a younger generation that is far more progressive and far more diverse.’’

A native of Fall River, Dionne identifies himself as a liberal, but one who wishes for “a better kind of conservatism,’’ one that might exemplify what Edmund Burke described as “a disposition to preserve and an ability to improve.’’ After all, he added, “a conservatism that is too radical is a problem for all of us, not just conservatives.’’

Dionne will read 6 p.m. Tuesday at the Brattle Theatre, 40 Brattle St., Cambridge (tickets $5, at http://www.harvard.com/event/e.j._dionne_jr1/).

Kate Tuttle, a writer and editor, can be reached at kate.tuttle@gmail.com.