Does a promise of leniency render a confession involuntary?

Although the People do not argue it, any suggestion that only express promises of a benefit render a confession involuntary must be rejected. Both the case law and common sense are to the contrary. Implied promises of leniency render a confession inadmissible. (People v. Jimenez supra, 21 Cal.3d 595, 611-612, 147 Cal.Rptr. 172, 580 P.2d 672; People v. Sultana, supra, 204 Cal.App.3d 511, 522, 251 Cal.Rptr. 115.) And for good reason. To hold otherwise would simply permit police to do indirectly what they could not do directly.