According to a study that was done (I believe by the NEA, can't remember exactly) the estimate of teachers that are members of the NEA is about 25% of all teachers.
The majority of teachers that I know or have met (I have met them from all 50 states because of my activity with the business club FBLA) are very conservative.
The NEA on a national level is run by a small minority of their own members. Even some of the NEA members disagree with what goes on and are trying to take their union back.
I support, wholeheartedly, merit pay. I despise the fact that someone that doesn't put any effort in, but has taught the same amount of years that I have, makes the same amount of money I do.
As you probably know, FQ, in TN, they are trying to introduce merit pay. The TEA is "negotiating" how it should be implemented. At our most recent faculty meeting, their representative said that they wanted our input on how to equitably distribute the merit pay since we are all hard working teachers. I started tapping the table loudly and said, "How communistic can you get?" That drew laughter from the majority of our teachers and our principal.
As you can guess, I am not a member and am proud to say that after my first year of teaching (the only year I was a member), our school has gone from 100% membership to less than 15% due to some hard work on my part and one other teacher. I won't be satisfied till we are at 0%.

"Students are encouraged to mingle with the midgets." - Mr. Jones' 1st Block Class