It's very hard to make change nationally when it comes to public policy. Typically, if it happens, it happens because of a grass roots effort that picks up steam and the attenion of the media, politicians and big-name activitists. 

However, in your local community, making change happen might appear to be easier because of the easier access you might have to councilors, the mayor, etc. Then again, politics is politics (regardless of all politics being local, as Tip used to say).