The Court of Appeals went through the steps as follows:
1. Defendant was charged with tax evasion for 2000-2002 and tax obstruction under Section § 7212(a).
2. At trial, St. Pierre's underpayment of her personal taxes was undisputed; the central issue was whether St. Pierre had the requisite state of mind for the various offenses.
3. One of the accountants testified "that St. Pierre had been told to deposit company income into Staab's corporate bank account, as such deposits would enable the accountants to track Staab income that had to be reported on Staab's corporate and St. Pierre's personal income tax returns." There was apparently other "evidence that St. Pierre's accountants had explained to her -- in connection with past failures that she had claimed to be inadvertent -- the obligation to report company income on Staab's books."
4. Without telling her accountants, St. Pierre established at least 10 bank accounts unknown to the accoutants and deposited business revenue into the accounts, diverting over 3,000 business checks into those accounts. "Records indicated unreported income of $1,248,327 for the three-year period; the taxes avoided by the failure to report this income amounted to over $500,000, apart from interest."
5. This pattern existed in the years 2000-2002. By 2002 a tax audit had started, and the defendant doctored documents to affect the audit.
6. The jury acquitted the defendant of evasion for 2000 & 2001, but convicted for tax evasion in 2002 and for obstruction. The Court noted (fn. 1): "Although the unpaid taxes for 2000 and 2001 were also substantial, the government suggests that the jury may have given St. Pierre the benefit of the doubt as to her understanding of her obligations prior to 2002. By the time she signed her 2002 return, a tax audit was underway and St. Pierre had told IRS auditors that she understood her obligation to report company income."
7. The defendant claimed on appeal that the trial court's exclusion of the proffered expert testimony violated her Sixth Amendment right to present a defense and that the trial court misapplied the rules of evidence in denying the testimony.
8. The Court of Appeals rejected the defendant's claim as follows (footnote omitted):
At first blush, one might think that whether St. Pierre's accountants exercised due care was flatly irrelevant to any issue properly in the case. Mere failure of the accountants to detect her under-reporting or to give St. Pierre better directions, even if negligent, would not be a defense to a knowing effort by St. Pierre to evade taxes or willfully create false documents. n2 The jury was told what elements were required to prove tax evasion and obstruction, and the evidence amply permitted the jury to find that St. Pierre had the requisite consciousness of wrongdoing.
The trial judge was probably wise to invoke Rule 403, thereby assuming arguendo some possible relevance of the proffered evidence, however minimal or doubtful. Cases can be imagined where an accountant's neglect could bear on the likelihood that a taxpayer's under-reporting was due to honest reliance rather than deliberate dishonesty. And, although not at all a straightforward inference in this case, in some situations the professional standards governing accountants might in turn have some bearing on whether there was such neglect.
However, the scheme as charged and proved in this case was not hospitable to such reasoning. The government's evidence allowed the jury to find that St. Pierre, in diverting company income to personal ends but not reporting it as income to the company or herself, had acted against warnings; that St. Pierre had used multiple personal accounts not disclosed to accountants; that the scale of diversion was huge; that the accountants were unaware of most of what was occurring; and that St. Pierre herself engaged in creating false documents to cover her tracks.
By contrast, St. Pierre's proposed accounting standards evidence, by shifting the focus to whether the accountants were doing a good job, did have a potential to confuse and mislead a jury -- precisely because her accountants' failure to prevent the fraud would not be a defense. To the extent that St. Pierre relied on what she said her accountants or lawyer or bankers told her, she was permitted to offer such evidence. Her own beliefs about what they were responsible for doing might also be pertinent to her state of mind. Evidence of accounting standards, unknown to St. Pierre, had at best little tendency to negate the damning inferences against her, and Rule 403 was properly applied."