In the case of Humberto Fidel Regalado Cuellar v. United States, 2007, the U.S Supreme Court examined whether merely hiding funds during transport constitutes money laundering under federal law. Cuellar was arrested while attempting to smuggle a large sum of money from Texas into Mexico and was charged with international money laundering. The defendant argued that he should not be convicted because his actions did not constitute "money laundering" as defined by law - which requires proceeds to be transported with intent to conceal or disguise unlawful nature, location, source etc., rather than just concealing the transportation itself. The court ruled in favor of Cuellar stating that simply hiding funds during transport does not meet the statutory definition for 'money laundering'. It held that prosecutors must prove beyond reasonable doubt that a defendant intended more than just secret transportation; they must show an intention to create appearance of legitimate wealth. This decision clarified interpretation and application of anti-money-laundering statutes.

In the case of Humberto Fidel Regalado Cuellar v. United States, Justice Alito's dissenting opinion argued that the majority misinterpreted 18 U.S.C §1956(a)(2)(B)(i), a federal money laundering statute. He contended that it was not necessary for the government to prove that a defendant attempted to create an appearance of legitimate wealth in order to convict them under this law. Instead, he believed any act taken by a defendant with intent to conceal or disguise properties related to unlawful activity could be considered as money laundering. In his view, transporting hidden funds across borders should fall within these parameters and thus constitute money laundering regardless of whether there is an attempt made at creating an illusion of legitimacy around those funds.