security objectives at the time. In other words, the outcome of a successful deterrent threat was less appealing to Israeli strategists, primarily because Israel stood to gain from a limited Syrian invasion into Lebanon: they could ensure military support for the Maronites, who were on the verge of defeat, without getting involved in a confrontation; avoid jeopardizing their relations with the United States; be certain that a Syrian intervention would affect Arab unity; and promote a battle between Syrian forces and the PLO.
In order to render sound judgments about deterrence success or failure in the Lebanese crisis, therefore, a distinction must be drawn between Israel's intrinsic and strategic interests ( Jervis 1979). Although Syria was deterred from intervening in a way that was contrary to the intrinsic interests of Israel (its survival, territorial integrity, and so forth), Syria still invaded in a way that challenged many of Israel's "strategic" interests as stipulated in the red lines. Unlike intrinsic interests, which are rarely questioned, "judgments about the credibility of strategic interests may turn on efforts a defender makes to convey its resolve" ( Lebow and Stein 1989b, 63). If success is measured, at least in part, on the basis of whether the strategic objectives of the deterrer are satisfied, then Syria's invasion should be considered a partial deterrence failure; Israel's efforts to convey its commitments and resolve were restricted (intentionally or not) and provided Syria with a window of opportunity to move into Lebanon. On the other hand, if the outcome is assessed in terms of Israel's intrinsic interests, the case should be classified as a deterrence success, both in terms of theory and strategy, because the most important of the five conditions (the geographical line ten kilometres south of the Beirut-Damascus highway) was not violated. Depending on which of the red line conditions one highlights and the specific time frame one selects, the final coding of this case will change. 27
As the case just discussed demonstrates, identifying cases appropriate for evaluating deterrence theory within the Huth-Russett/ Lebow-Stein research program is problematic. Although the authors' efforts have been constructive, there are numerous problems with the success/ failure framework that cannot easily be overcome through reference to the historical record. Based on the preceding analysis, new directions for aggregate testing of nuclear deterrence are presented in chapter 3. The alternative approach uses international crisis data to test several new propositions derived from deterrence theory, rational choice theory, and coercive diplomacy more generally. The most