When you have insisted on the politician's support for your position, they will then try to buy you off. Here is where most grassroots leaders fail. Power and Influence and Selling Out Politics can be seductive. These are the trinkets for which leaders sell our their political agenda. Of course, most everyone thinks he is strong enough, smart enough, and committed enough not to sell out.
Few people are.
Before long, instead of delivering to the politician the grassroots' message to pass legislation, you become the politician's representative, telling your people what they must settle for. Right now, today, decide whether you want influence or power. Influence is calling a politician and having him take your call. He listens to what you want, and may or may not do it. It is what most grassroots leaders end up settling for.