This article has two main goals, one is to explore whether the improvement in cross-Strait relations has increased both the risk of entrapment for Washington and the fear of abandonment for Taipei since 2008, and the other is to examine why the United States provides Taiwan with strategic reassurance. The two main international relations (IR) theories applied in this article are Charles Lipson's theory of informal alliance and Glenn H. Snyder's theory of security dilemma in alliance politics. Taipei may be hoping that when cross-Strait negotiations move from economic and Cultural issues to politically sensitive ones, Washington will play the role of guarantor or supervisor: However, the United States may believe that playing such a role would increase its risk of entrapment. On the other hand, fear of abandonment for Taiwan is more likely to arise when the cross-Strait relationship further deepens and expands. While most observers believe that Taiwan's fear of abandonment is greater than Washington's risk of entrapment, some are of the opinion that the rise of China will eventually allow Beijing to intimidate Taipei, leading to Taipei's submission, if cross-Strait relations get out of control. Fortunately, bearing China's expansionist behavior in 2010 in mind, the United States is taking steps to focus its attention on Asia once again, and also emphasizing that Taiwan is an important security and economic partner, thereby easing Taipei's fear of abandonment. Thus, the main conclusion of this article is that while a relatively swift improvement in cross-Strait relations may increase the risk of entrapment for Washington and the fear of abandonment for Taipei, it seems that both the United States and Taiwan have reached a consensus that their current informal alliance should be nurtured by means of strategic reassurance, given China's potentially expansionist behavior.
