Exactly, our local District Attorney had a 100% conviction rate as DA because he handed off anything he wasn't positive he could win to his Assistant DAs.
Also many times the Fed can pick and choose what they prosecute more so than local prosecutors. Many Federal cases are instead of or in addition to local prosecution, so they aren't always completely necessary because the defendant will likely get local jail time anyway.
Also many times the Fed can pick and choose what they prosecute more so than local prosecutors. Many Federal cases are instead of or in addition to local prosecution, so they aren't always completely necessary because the defendant will likely get local jail time anyway.