With closing arguments in the Enron trial set to begin today, it's worth looking at the reaction over the last week to the news that Judge Lake dealt Ken Lay and Jeff Skilling a serious blow when he said he would instruct jurors that "deliberate ignorance", the Sgt Schultz defence, of fraud at the collapsed energy company was not a justifiable defense.

From one reading, the so-called "Ostrich instruction" lowers the burden of proof. But it can also backfire on the prosecution which had argued that argued that Lay and Skilling deliberately chose to lie and mislead investors and employees.

Can you have it both ways? I'm not sure you can. There is an interesting discussion of this in the New York Times.

In the blogosphere, Houston attorney Tom Kirkendall has posted an entry that says the ostrich instruction is not the crunch issue. He says the bigger question is whether Lay and Skilling have had a fair trial:

"Because of the almost unprecedented negative media coverage relating to Lay, Skilling and Enron prior to this trial, the much more important issue is whether the jury was truly impartial at the outset of the case. If they were not, then Lay and Skilling's fate was sealed from the beginning and the Ostrich instruction is not going to affect the jury's decision in the slightest. On the other hand, if the jurors are truly impartial -- particularly the leaders on the jury who will guide the panel to a decision once deliberations begin -- then my sense is that the jurors are unlikely to rely on something as amorphous as the Ostrich instruction to convict these men in a case of this nature."

It's more likely to hurt Lay than Skilling, according to the CFO Blog Ron's Rant. According to this argument, Skilling never said he didn't know what was going on which makes an appeal likely if the jury goes against him: "In other words, allowing conviction for "ostrich" behavior seems to increase the likelihood that Chuckles will do time but that Skilling will skate."

All of this means one thing: proving guilt beyond reasonable doubt in this trial is no sure bet. For a good examination, read Bloomberg columnist Ann Woolner's analysis.

Still, some have cut right to the chase. In a neat piece of marketing, SmartPros is asking readers to vote on whether Lay and Skilling are guilty or whether they should walk.