The Collector v. Day was a United States Supreme Court case that was decided in 1870. The case involved a dispute between the Collector of Internal Revenue and William B. Day, a former collector of taxes in the District of Columbia. Day had been appointed by President Abraham Lincoln in 1861 to collect taxes in the District of Columbia. Day had collected taxes from various individuals and businesses in the District, but had failed to remit the taxes to the United States Treasury. The Collector of Internal Revenue sued Day for the amount of taxes that had not been remitted. The Supreme Court held that Day was liable for the taxes that he had collected but failed to remit. The Court reasoned that Day had a duty to remit the taxes to the United States Treasury, and that he was liable for any taxes that he had collected but failed to remit. The Court also held that Day was not entitled to any compensation for his services as a collector of taxes, as he had failed to fulfill his duty to remit the taxes to the United States Treasury. The Collector v. Day is an important case in the history of the United States Supreme Court, as it established the principle that a collector of taxes is liable for any taxes that he has collected but failed to remit. The case also established that a collector of taxes is not entitled to any compensation for his services if he fails to fulfill his duty to remit the taxes to the United States Treasury.

The Collector v. Day was a case heard by the United States Supreme Court in 1870 that concerned the interpretation of an act passed by Congress in 1862. The majority opinion held that Congress had intended to exempt from taxation any salary paid to a federal judge, even if it was received after his term expired and he no longer served as a judge. However, Justice Field dissented from this decision, arguing that such an exemption would be unconstitutional because it violated Article I Section 9 of the Constitution which prohibits any law granting titles of nobility or creating special privileges for certain individuals without consent from all states involved. He argued further that since there were some states who did not agree with this exemption when they ratified the Constitution, then Congress could not pass such legislation without their approval first. He concluded by stating that while he believed judges should receive fair compensation for their services rendered to society, they should also pay taxes like everyone else unless specifically exempted through constitutional means.