Over the past two decades, Beijing has deployed its classical hierarchy of warning signals at least four times regarding Taiwan.

In past responses to an international crisis or dispute that directly affected Chinese interests, Beijing has deployed a hierarchy of authoritative leadership statements, official protests, and press commentary intended to assert its claims and to deter its antagonists. If the crisis persists and Beijing perceives its interests are not satisfactorily taken into account, its statements escalate in level and may include at first implicit and thereafter increasingly explicit warnings that it may use military force to achieve its goals. This was the case in each of the major instances in which Beijing has resorted to military force—in Korea in 1950, in the Sino-Indian border dispute in 1961–1962, in the Sino-Soviet border dispute in 1968–1969, and in China’s attack on northern Vietnam in 1979. It was also true in instances in which Beijing’s effort at deterrence succeeded and ultimately stopped short of using military force, as, for example, with respect to the American combat effort in Vietnam in 1965–1968 and to the debates in Taiwan in 1991 about delimiting the ROC’s sovereignty claims

Although defining a political-military “crisis” can become extremely complicated, this analysis will employ a simple definition. A crisis is defined as an unanticipated event perceived as threatening high-level interests of at least one set of decisionmakers while providing only a limited time for response