Government is full of people who want to do a really good job and save the world. These people don’t advance. If you want to advance, figure out what motivates your agency. The motivating force is usually closely tied to how your agency obtains funding (for example, your agency may have to beg Congress for money every so often). Regardless of your own beliefs, you’ll do fine is you support your agencies motivating force.
Don’t ever take a strong, non-nuanced position in writing.
Keep all your emails.
Learn to like the politics. It’s not going to go away – it’s part of the job. You’ll advance faster and enjoy your job if you learn to like the politics.
Enjoy – the benefits and salary (in terms of dollars per hour) are great!