In the case of Bank of British North America v. Cooper in 1890, the U.S Supreme Court was tasked with determining whether a bank could recover money it had loaned to a borrower who subsequently declared bankruptcy before repaying the debt. The defendant, Mr. Cooper, borrowed $10,000 from the plaintiff (Bank of British North America) and gave them two promissory notes as security for repayment. However, he later filed for bankruptcy without having paid back any part of his debt to the bank. The main issue at hand was whether or not these promissory notes were valid under American law since they were issued under Canadian law where interest rates are higher than those allowed by American legislation. Ultimately, the court ruled in favor of Bank of British North America stating that while usury laws would typically render such an agreement void due to excessive interest rates; this did not apply because both parties involved were aware that Canadian law governed their contract when entering into it and thus agreed upon its terms knowingly and willingly.

In the dissenting opinion for Bank of British North America v. Cooper, Justice Lamar disagreed with the majority's interpretation of the law and its application to this case. He argued that a bank should not be allowed to recover money paid under mistake when it was due to their own negligence or oversight in failing to discover relevant facts about an individual's bankruptcy status. In his view, if a bank has sufficient notice or information leading them towards further inquiry into someone’s financial situation and they fail to do so, then they must bear the consequences of any subsequent error made as a result of their lackadaisical approach. The justice emphasized that banks have both legal and moral obligations in such situations which cannot be ignored simply because it may lead them into making mistakes from time-to-time.