Section 3--408. Consideration.

Want or failure of consideration is a defense as against any person
not having the rights of a holder in due course (Section 3--305), except
that no consideration is necessary for an instrument or obligation
thereon given in payment of or as security for an antecedent obligation
of any kind. Nothing in this section shall be taken to displace any
statute outside this Act under which a promise is enforceable
notwithstanding lack or failure of consideration. Partial failure of
consideration is a defense pro tanto whether or not the failure is in an
ascertained or liquidated amount.