Can a defendant seek release by way of habeas corpus because of errors committed during the trial?

It is elementary that one confined on a judgment of conviction cannot seek release by way of habeas corpus because of errors committed during the trial (People ex rel. Carr v. Martin, 286 N.Y. 27, 35 N.E.2d 636). In exception exists where the court lacks jurisdiction. To evaluate this exception the term 'jurisdiction' must be used in its exact sense, and not loosely. It is often stated that where a defense exists the court lacks jurisdiction. This is a misuse of the word. No court lacks the power to try an accused merely because he asserts a defense. The defense must be shown to be valid. And the court otherwise empowered to hear the cause must pass on the validity of the defense. A claimed error in the determination of the issue raised by the defense is in no different category than any other error. The remedy is by way of appeal.