For young lawyers wanting to "learn" how to get involved in politics, landing a job as a legislative director is a great way to start. In fact, if you travel to D.C. and hang around long enough, you will learn that an awful lot of legislative directors are attorneys. The reasons for that are simple enough -- lawyers learn the legislative process quite well, understand the Constitution better than most people and those are skills that are tailor made for Congressmen looking for advice.
Besides, a lot of lawyers get disenchanted with practicing law in a hurry. What they learned in law school translates very well to a legislative office.