In the 1911 case of Fairbanks v. United States, the U.S. Supreme Court ruled that a person could not be convicted for using mail to defraud another individual if they did not know their actions were fraudulent. The defendant, Mr. Fairbanks, had been charged with fraudulently obtaining money through mail by selling shares in a company he falsely claimed was profitable when it wasn't actually making any profit at all. However, evidence suggested that Mr. Fairbanks genuinely believed his claims about the company's profitability and thus didn't knowingly commit fraud. The court held that an essential element of mail fraud is intent to defraud; without this intention or knowledge of deceitful conduct on part of the accused party, no crime can be said to have occurred under federal law pertaining to use of mails for fraudulent purposes (18 USC §1341). Therefore, since there was reasonable doubt as to whether Mr.Fairbank knew his statements were false when he made them - i.e., whether he intended to deceive potential investors - his conviction was overturned.

In the dissenting opinion for Fairbanks v. United States, it was argued that the government did not have a right to tax property owned by citizens in Alaska because at the time of taxation, Alaska was not yet incorporated into the Union as a state or territory. The dissenting justices believed that this violated constitutional principles and infringed upon individual rights. They contended that while Congress had broad powers over territories, these powers were limited by fundamental guarantees within the Constitution itself - including protections against unjust taxation without representation or due process. Furthermore, they disagreed with majority's interpretation of "public lands," arguing instead that private properties should be exempt from such taxes until formal incorporation occurs.