Derek Slater is my former colleague at the Electronic Frontier Foundation, now serving as a policy analyst at Google. He's just published a barn-burning essay called "#noimnotgoingtolawschool: Or, Why I Love Legal Clinics as well as Lawyers and Law Professors That See Their Primary Job As Helping Students Reach Their Goals, Or, Disrupting Law Schools." Slater indicts the legal education industry as a system that produces debt-ridden, half-trained half-lawyers who have to go on to firms in order to actually learn to practice law. He calls for a refactoring of the legal education system around legal clinics, which, he says, will prepare lawyers to actually help clients.
If the thing you want to have an impact on is politics and/or the legal system:
then I'd still recommend you probably be an engineer, and that you direct your engineering talents to politics.
In the alternative: I would recommend you focus on where you have passionate beliefs, and surround yourself with really smart engineers and really smart lawyers. I would apprentice with those types of people, and show a willingness to get your hands dirty and work hard toward what they're passionate about…
The first model I'd look at is how colleges are training really amazing software engineers. There is nothing inherently special about the people who are software engineers that make them better or more able to change the world. They're not inherently smarter than lawyers. They are not unique or special snowflakes either.
They have just been trained better. The difference is that they have been trained to be immediately effective in the world. They are trained in ways that allow them to contribute to the companies they join right out of the gate. They know how to code.
Law students are currently the equivalent of someone asking Google or Facebook for a job, and saying "I don't know how to code, but I know a lot of theory about the Web and I've looked at a ton of websites. I'm really smart. So hire me and teach me how to code, ok?"
(Image: UC Berkeley Law School Quote, a Creative Commons Attribution (2.0) image from taylar's photostream)