The "defense attorney" aspect of law
It's not your job to lie, deceive, and cheat to get your client acquitted. You give them the best legal defense so that they receive the due process that everyone has a right to.
*"The job of the defense is to make sure the prosecution does theirs."*
If your client is guilty, then the prosecution should be able to prove it fair and square. If they can't then the quality of evidence does not meet the minimum standard and your client should go free. Full stop.
Does that mean the occasional guilty person gets away with it? Yeah. But far worse is a system where innocent people are more likely to go to jail because a s**tty prosecutor's weak arguments were accepted.
A good defense attorney would recognize a losing case and just try to get the best deal for their client, and getting the weaker charges dropped (in case the prosecutor just decides to "throw the book" at them)