Mersman v. Werges & Another was a United States Supreme Court case that dealt with the issue of whether a mortgagee could assign a mortgage without the consent of the mortgagor. The case involved a dispute between two parties, Mersman and Werges, over a mortgage on a piece of property. Mersman had originally mortgaged the property to Werges, but then assigned the mortgage to another party without Werges' consent. Werges argued that the assignment was invalid because it had not been done with his consent. The Supreme Court ultimately ruled in favor of Mersman, holding that a mortgagee could assign a mortgage without the consent of the mortgagor. The Court reasoned that the mortgagor had already given his consent to the mortgage when he originally entered into the agreement, and that the mortgagee was free to assign the mortgage to another party without the mortgagor's consent. The Court also noted that the mortgagor had no right to interfere with the mortgagee's ability to assign the mortgage.

In Mersman v. Werges & Another, the Supreme Court was asked to decide whether a mortgagee could bring an action against mortgagors for nonpayment of interest on a note secured by real estate in Missouri. The majority opinion held that the mortgagee had no right to sue because it did not have legal title to the property and therefore lacked standing under state law. Justice Field dissented from this decision, arguing that while it is true that only those with legal title may bring suit in such cases, there are exceptions when equity demands recognition of rights which do not depend upon technicalities or formalities. In this case, he argued, justice requires recognizing the rights of both parties: if one party has been deprived of their money due them without fault on their part then they should be allowed recourse through litigation; conversely if another party has received money unjustly then they should also be made accountable for repayment.