Hi EndofMysteries, I vote and write to senators and representatives a couple of times a year on topics that interest me like increasing social requirements for organizations to qualify for tax exempt status (applies to the WTBTS and dangerous cults), increasing transparency of the Federal Reserve, etc.
If you want to send comments to Senators click on http://www.senate.gov/general/contact_information/senators_cfm.cfm and to Representatives click on http://www.house.gov/representatives/. When writing to them be polite, to the point, and concise. Do not expect them to respond to your email nor that their response is relevant to what you wrote them about.
As you alluded to in your comments, it is important for many people to write to the same politician to get noticed. Also, the issue should be as general as possible with something that will benefit the politician. It is better to increase societal requirements for non-profit organizations than be against the Watchtower, and, if the politician wants to be viewed as fiscally responsible, to increase government revenue if non-profits do not comply.
Best of Wishes for you writing to politicians. Think of ways to overcome your frustrations and increase your influence.
Peace be with you and everyone, who you love,
Robert
P.S. - BOTR is right about politicians would not overtly infringe on 1st Amendment rights, but I feel that non-profit tax laws can be changed that do not infringe on 1st Amendment rights and promote social responsibility like child protection, anti-discrimination, and prevent organizations from using undue influence to promote ostracizing members (i.e., shunning). If BOTR is right, then I would like her to explain how the IRS is able to declare that a religious charity no longer has tax exempt status for funding terrorizm?