I agree. I think some are better than others at it, but in the end, it will come down to the ability of legal counsel to work a case. Which doesn't always equate to justice. However, in the case of the criminals, if they get off once, they did to find ways to get back in front of a judge and jury, so in those cases of repeat offenders, they're bound to trip over their own ego, arrogance, ineptness or compulsion, however you wish to define it.
It would be good if both sides of the equation were working towards justice and truth, rather than solely the best interests of who they represent. A lot more guilty and a lot less innocent would end up in prison.