I was under the impression that it was widely considered true that the threat of jail does act as a deterrent; and that it was longer jails times (doing more so

I was under the impression that it was widely considered true that the threat of jail does act as a deterrent; and that it was longer jails times (doing more so) that was open to debate. Are you arguing that, if there was no jail time for anything at all, people would not commit more crimes?