Maxwell Lewis's nickname—Loophole Lewis—didn't come from thin air. The guy's motto is, "If you can't find a loophole for your client, go out and invent one" (94.11). That shady way of approaching life keeps Maxwell's hands busy (and dirty), and when it comes trial time (he's defending the White Raiders), he's willing to lie for his clients and generally do whatever it takes to get these racist murderers off scot-free.
Here's the thing, though: We're supposed to hate Maxwell (and we do), but one of the reasons he's in the novel is to show just how endemic this racist attitude has become. Plenty of people in the town support Maxwell because they believe he's perfectly justified for defending the White Raiders. And while we know this is despicable from a moral standpoint, it paints a pretty clear picture of the world our characters live in.