This Wall Street Journal ($) article addresses the knotty problem of proving mens rea (i.e., intent) in corporate criminal cases. As the Journal article notes, the problem, in short, is this:

It may be obvious that an executive did something wrong, but that doesn’t mean he intended to do anything wrong.
And therein lies the biggest hurdle for prosecutors in corporate-corruption cases. Prosecutors must prove not only that the accused did something bad but also that they meant to do something bad.

The article notes that proving criminal intent becomes particularly difficult when ccorporate executives commit wrongful acts openly and on advice of counsel, accountants and consultants:

Many executives accused of improper accounting argue that they had no criminal intent by insisting that that they relied on advice or approval from lawyers, boards of directors or auditors. “In dealing with arcane areas,” an advice-of-counsel defense can be “a silver bullet,” says George Canellos, a former federal prosecutor. Prosecutors often counter that the defendant didn’t give the lawyer complete information.
In the Tyco trial, a key defense argument was that the defendants operated openly. All of their actions, they stressed, were recorded in company records, known by numerous employees and, in many cases, by outside auditors. Jurors say those arguments echoed powerfully, leading about half to lean toward acquittal initially. “It was something the defense hammered on, with a lot of effectiveness,” says juror Peter McEntegart.

And, as Professor Ribstein notes over at Ideablog:

Things get even murkier in securities fraud cases, where the perpetrator is not only not stealing, but may actually think he’s being loyal to shareholders by, for example, protecting their shares from short-term earnings glitches.
Of course this thinking is misguided and wrong, but should it be criminal? Criminalization discourages beneficial risk-taking. Even worse, applying criminal law to ordinary behavior risks diluting the moral force of the law.

Professor Ribstein makes an insightful point. If we criminalize business risk-taking partly because it is difficult to prove criminal intent in most business cases, then we are eventually going to discourage business risk-taking, which will have detrimental consequences on economic development and job creation.
To make matters worse, demagogues in the political field have seized upon corporate executives as popular political enemies. Thus, they have promoted criminal laws that assess criminal sanctions that are completely out of proportion to the nature of the business crime — just plug the name “Jamie Olis” into this blog’s search engine to read about a prime example of that phenomenom. Moreover, those same politicians have also passed laws that constrict the power of judges to use their discretion and good judgment to modify a criminal sanction to make it appropriate to the crime.
The bottom line is this — railing against capitalist roaders may be good politics, but it is contrary to fundamental American principles of justice.