The character of LBJ in this film is a total fantasy

George Reedy worked for Johnson for 14 years. Here's some quotes from his book, Lyndon B. Johnson: A Memoir, cited online at http://www.economicpolicyjournal.com/2013/01/lbj-paranoid-narcissist-b ully-sadist.html

Pg x:
"There was no sense in which he could be described as a pleasant man. His manners were atrocious- not just slovenly but frequently calculated to give offense. Relaxation was something he did not understand and would not accord to others. He was a bully who would exercise merciless sarcasm on people who could not fight back but could only take it."

Pg 2:
"He had a remarkable capacity to convince himself that he held the principles he should hold at any given time, and there was something charming about the air of injured innocence with which he would treat anyone who brought forth evidence that he had held other views in the past. It was not an act. His whole life was lived in the present and he was tenacious in his conviction that history always conformed to current necessities."

Pg 3:
"To complicate the picture, his own view of what had happened frequently shifted. To the outside world, this appeared as a form of mendacity. It is my firm belief, from close association over a number of years, that the man never told a deliberate lie. But he had a fantastic capacity to persuade himself that the "truth" which was convenient for the present was the truth and anything that conflicted with it was the prevarication of enemies. He literally willed what was in his mind to be reality and, as he was a master at imposing his will upon the people, the society, and the world around him, he saw no reason for history to be exempt from the process..."

Pg 171-172:
"There were a few key traits to his personality and it is unlikely that he shed them. As a human being he was a miserable person- a bully, sadist, lout and egoist. He had no sense of loyalty (despite his protestations that it was a quality that he valued above all others) and he enjoyed tormenting those who had done the most for him. He seemed to take a special delight in humiliating those who had cast their lot in with him. It may well be that this was the result of a form of self-loathing in which he concluded that there had to be something wrong with anyone who would associate with him.

"His lapses from civilized conduct were deliberate and usually intended to subordinate someone else to his will. He did disgusting things because he realized other people had to pretend that they did not mind. It was his method of bending them to his designs."

It would have been a better story if it had been this LBJ. Instead of "Oops, I got into a war because I didn't understand the Vietnamese."