Malcom "Mal" Reynolds wrote:
"Falsus in uno, falsus in omnibus," False in one, false in all.

Suppose you were trying to make the point that Paul Ryan does not
possess traditional American values. Suppose further that in trying
to make that claim, you mention he's really an alien from another
planet and has "Soup is Good Food" tattooed on his forehead.

Who would take you seriously?

Lesson is, even when mentioning points not essential to your
argument, it is prudent to be as accurate as possible.

I agree, accuracy is highly desirable, but it doesn't matter a wit
that I got the number of congresspeople wrong. in fact, since my
number was high, my point becomes even more relevant. A small group
of legislators and they can't pass laws

To me, and others, it matters a great deal that you got the number of
congress-critters wrong. It fatally wounds your entire argument. If you err
on small matters, it's not only likely, but probable, that your main
argument is likewise wrong. In other words, if you assert completely
unbelievable things of minor importance, you are probably wrong on your
central message.

From now on, when you put forth some poignant and heart-felt belief, you
will get the rejoinder: "Are you as sure about that as you were that there
were 700 members of Congress?"

What you SHOULD have done was respond: "Of course there are 535 members of
Congress. I can't imagine how I came up with such an absurd number. I
apologize for the mistake."