Micah, I think the real test here is that a law-and-order message has worked for non-incumbent campaigns. Richard Nixon in 1968 is the often-cited case, but it helped that an unpopular war in Vietnam and civil strife made Lyndon Johnson more unpopular and served as an anchor for Hubert Humphrey. In 1988, George H.W. Bush was the incumbent vice president, but Ronald Reagan was relatively popular, so the Willie Horton attack probably had a better chance of working.