http://www.chacha.com/question/what-percent-of-teachers-are-liberal
The stats from this link appear legit, but stats are usually skewed so feel free to post something different.
Why are more teachers Democrats? Because of the Teachers Union. Teachers are, or were, very well protected by the Democrats, hence the very high percentage of TU political funds being given to Democrats. The traditional belief had been that it is in the teachers' interest to have Democrats in office. Things have minimally shifted when Democrats were unable to protect unions during recent attempts to break unions.
Now why is it that Liberals drift toward the profession initially? My guess is Liberals tend to be more inclined to want to help people perceived to be in need, which is the biggest thing I like about Liberals. They tend to believe every individual deserves an equal chance and feel compelled to extend that chance through whatever means they can, whether through teaching, going abroad to help 3rd world underdeveloped citizens, that type of thing. I've always found those traits to be highly admirable, so this is NOT a knock or slight in any way.
Some professions just attract one political slant more than others. Accountants tend to be more Conservative would be an example of the opposite to teachers being Liberal.
Now, while the students can independently form their own opinions, the fact remains teachers will explain things from their perspective regardless of how many rules or laws demand they present material in a neutral fashion. Enough studies have been done to show people express themselves in many ways and their views become evident regardless of what is said. Whether through inflections, body language, phrasing, or follow up questions, the true feelings are presented. Now some are better at explaining both sides than others, or remaining neutral about topics, but definitely not all, and in my experience the more a person leans to an extreme the more their beliefs come through in their teaching, whether Liberal or Conservative.
Just because some of you wish to be combative about what I am saying does not make this more or less real, but take a moment and think back to who your teachers were and whether you can identify them as Liberal or Conservative. Some you won't know for certain, so those were the more moderate teachers. Others were pretty blatant and left little if any doubt. Try to tally up how many of each you experienced and whether or not you liked them as a teacher or not. You might be surprised at what is revealed about them and yourself.
But go ahead and keep bashing me as stupid or whatever, as that is far easier than taking a breath and considering what I am saying and thinking it through.