Chris Lehmann does not like All the King's Men:

"Why Americans can't write political fiction." by Christopher Lehmann :

In most respects, Warren's novel has aged poorly. Its Faulknerian prose manages to be both purple and flat while its political reflections are just banal. ("Man is conceived in sin and born of corruption," runs Willie Stark's oft-quoted motto, "and he passes from the stink of the didie to the stench of the shroud"--a nugget of wisdom as hard-won as it is subtly voiced.) At the simple level of characterization, Jack Burden's odyssey is unpersuasive--his alleged innocence is more a product of tedious grad school soliloquizing than any discernible virtue. Likewise, Willie Stark's temptation of Burden into the lurid exercise of demagogic power is pasteboard populism, an opportunity to score cheap points against a discredited leader like Long--and the grievously distorted political persuasion he represented--on behalf of what is ultimately an aristocratic conception of Old South noblesse oblige. Yet Warren's overheated language of sin and corruption does hearken back to the odd moral fastidiousness that shapes so much of the obdurate badness of American political fiction...

I did not read All the King's Men as scoring cheap points against Huey Long at all...

Shows how reading is an activity that takes place between the ears, and how your mileage may vary.