But an account debtor sometimes refuses to pay the secured party. In that instance, the secured party may elect to sue the account debtor to enforce its right to be paid. Account debtors have defended such claims based on the language of key UCC provisions. This article will discuss one of the arguments made by account debtors — that a mere security agreement does not give the lender an enforceable claim to its borrower’s accounts—and that a separate assignment of the account may be required.