In the case of Marinello v. United States, the Supreme Court ruled in favor of Carlo J. Marinello II who had been charged with violating a provision of the Internal Revenue Code that made it a felony to "corruptly or by force...endeavor to obstruct or impede the due administration" of tax law. The court held that this clause only applies when there is clear evidence that an individual was aware they were under investigation and attempted to interfere with said investigation. In his defense, Marinello argued he did not knowingly violate any known legal duty because he wasn't aware he was under IRS investigation at all times relevant to his charges. The ruling overturned a decision from 2nd U.S Circuit Court of Appeals which had upheld his conviction on those grounds.

In the dissenting opinion for Marinello v. United States, Justice Thomas, joined by Justice Alito, argued that the majority's interpretation of §7212(a) was too narrow and not in line with Congress' intent. They contended that this statute should be read to criminalize all acts of obstruction relating to a proceeding under the Internal Revenue Code (IRC), regardless if there is an ongoing audit or investigation. The dissenters believed that limiting its application only to specific proceedings would undermine its purpose as it could allow individuals who obstruct tax administration but have not been officially notified about any IRS proceeding to escape punishment. Furthermore, they pointed out that other federal obstruction statutes do not require an ongoing proceeding and are interpreted broadly; thus, §7212(a) should also be treated similarly.