The elastic scattering of kaons on {sup 12}C is investigated using Kerman-McManus-Thaler theory, and the effect of a {ital u}-channel term as well as the usual {ital t}-channel terms in the {ital K}{sup +}{ital N} {ital t} matrix is computed. So long as the total forward {ital K}{sup +}{ital N} scattering amplitude is fitted, its division in {ital t}- and {ital u}-channel terms is found to be immaterial. Thus the theoretical underestimate of the {ital K}{sup +}-nucleus cross section cannot be explained by the presence of a {ital u}-channel contribution. Higher-order Kerman-McManus-Thaler effects are estimated to be negligible. A comparison with previous investigations is made.