Now, the first time the judge denied McConaughey's request to move the trial (without checking the legal precedents), it was a screw-up on the part of the judge. When a judge fails to consider all the evidence in a legal motion, this is called a "reversible error" (which, in legalese, means the judge done crapped him the bed something fierce). Bad enough, in fact, for the whole show to be declared a mistrial, meaning the defendant gets a brand-spanking-new trial. McConaughey has two options: 1) tell the judge that he made a mistake and give him a chance to correct it or 2) don't tell the judge; keep the information a secret and hold onto it. McConaughey chose option 1. He informed the judge of the screw-up and gave the judge a new opportunity to review the information. And he still got rejected.
Here's what McConaughey should have done: nothing. When you see a judge has committed a reversible error, you shut the hell up. That's the ace you hold up your sleeve, the one you don't play until the last minute. McConaughey should have kept quiet about the reversible error until after the trial, because a judge making a reversible error is grounds for a mistrial. Let's say Samuel L. Jackson lost the trial -- that's when McConaughey should play the "reversible error" card and get a brand new judge, jury and trial. Holding onto a reversible error is like having a mulligan, or a Get-Out-of-Death-Penalty-Free card. He could have just waited for the outcome of the trial and then said, "Nah, I don't like that. Do over."
"Only this time, we all wear party hats."