After having been in the forefront of expanding mass incarceration from the 1970s to quite recently, conservatives in the states appear to be rethinking their positions on criminal justice. They are increasingly skeptical of the value of prison for at least some criminals, and open to alternatives to incarceration. But not all conservatives have moved at the same time, or to the same extent. This paper will examine the diffusion of conservative criminal justice reform ideas, in an effort to determine the precise mechanisms by which ideas spread across states. In particular, we will examine the role of cross-state policy entrepreneurs like the American Legislative Exchange Council, Right on Crime, and the State Policy Network as agents of diffusion, as well as the possible role played by social conservatives and business. A second purpose of the paper will be to explain what causes innovations in one state to be adopted by others. Is it that the ideas "work" in a policy analytic sense, or that their adoption in other states shows that they are politically viable or "ideologically plausible" to conservatives.