writes (my emphasis):
I am reminded of an exchange that took place between the historian
Francis Russell and John Dos Passos. In 1920, two Italian
anarchists—Nicola Sacco and Bartolomeo Vanzetti—were accused of killing a
security guard and an employee of a shoe factory during a payroll
robbery to finance their political subversions. Their trial, which
resulted in murder convictions for both, was manifestly unfair, and it
caused an eruption of sympathy and protest on the left.
Celebrities around the world rushed to the two men’s defense. One of
the leaders in this movement, who wrote extensively about the case, was
the novelist Dos Passos. Nonetheless, the two men were executed in 1927.
But in the 1960s Francis Russell produced new ballistics tests and
interviews to prove that one man, Sacco, had killed the two men at the
shoe factory; the other, Vanzetti, was innocent. He tried to show this
evidence to Dos Passos, who had given up his leftist ideas by that time.
Dos Passos told Russell he could not even hear evidence that would
unsettle his personal stake in the matter. He had invested too much of
his youthful energy and self-esteem in the case to reopen it even for
the slightest reconsideration. It would destroy his very identity, which
had been tied up in that passionate commitment.
That is the way people cling with ardor to causes they have felt honor-bound to maintain.
(Reminds me of how so many veterans of the New Deal just couldn't consider the possibility that Alger Hiss had been a spy for the Russians. His antagonist, Richard Nixon, was thought to be a red-baiting vulgarian.)
Maybe a good start would be to realize that it's human to get invested in a particular viewpoint. And then just check yourself from time to time.