The often misunderstood Zabriskie Point is Antonioni's political film, Antonioni's American film. Stylistically, it follows suit after "Blow-Up", meaning that the pace is faster than the previous epics, though certainly no less idiosyncratic.
Basically the common mistake is that the film glorifies the hippie generation. Not so.
The two protagonists come from vastly different environments. Mark from the "rebel" youths, Daria from an estate agency corporation. But in true Antonioni fashion, they are both alienated, both trying to escape their surroundings. Mark leaves a meeting of rebel students and Black Panthers disappointed with the verbose empty rhetoric, while Daria keeps uneasily being on the move with her car.
Antionioni, the master director, after portraying the rebelling youth as confused and shallow, then moves to the city. An environment saturated by corporatism, billboard advertisements, meaninglessness, that has to keep expanding to accommodate the similar expansion of the population, generating a profit at the same time. It is this environment that the two protagonists escape from, though it seems mostly out of coincidence.
Indeed, when Daria stops by a small village in the outskirts of the desert, the environment is just as suffocating, and the people just as lost cases, best exemplified by an old boxing champion, now reduced to a shadow of himself, sitting around drinking and smoking and talking nonsense. A stunning melancholy sequence, made even more powerful with the inclusion of some half wild children living around, brought in by some "benefactor" but "destroying a genuine piece of American history". In a not-so-obscure symbolism, there is Antonioni's opinion on the hippies. Just a half-positive glimpse in the canvas of human alienation.
And then there is the desert, the landscape used to devastating effect, by turns pure and terrifying, primeval, wild and dead. The sequence where the two protagonists make love, "joined" in fantasy by the "flower" generation reflects the similar sequence in "Red Desert", where Giuliana tells her son a story. It is a colorful intermission in a colorless landscape. A vivid half-fantasy in a suffocating reality.
The ending probably belongs to the pantheon of great endings in cinema, the Western civilization blown to pieces. A catharsis, an exorcism.
Antionioni's two "international" films (the British "Blow-Up" and the American "Zabriskie Point") are lesser efforts than the previous masterpieces, but that is largely because of the faster pace and the inevitably contrived settings (swinging London, flower-power America). But when it comes down to it, it's clear he hasn't lost the edge.