本文首先檢視了有關戰略三角和樞紐角色的文獻，比較了一八七五到一 八九○年間由俾斯麥所主導的德國和一九九○年代的美國這兩個非自願樞紐的 行為模式，並且分析了樞紐在兩翼間採取傾斜動作的原因。本文主要的發現是第 一，滿足的國家希望三邊家族型的三角關係，如果實際上形成了羅曼蒂克型的三 角關係，則其樞紐地位常不是爭取而來的，也就是所謂「非自願的樞紐」。第二， 對於非自願的樞紐而言，在兩個側翼間的傾斜不是由菁英的策略思考決定，而是 由國內政治決定。就美國的例子而言，在兩岸之間的傾斜是繫於選舉週期以及由 其所帶來的理想主義與現實主義之間的勢力消長。每當總統大選接近之時(選 前)，或當反對黨挑戰執政黨成功之時(選後)，美國的中國政策就會向台灣傾斜; 而在選間期當政治菁英比較不受到國內政冶壓力影響之時，現實主義就會抬頭， 華府的中國政策就會向北京靠攏。第三，和自願的樞紐比較起來，非自願的樞紐 對於本身的角色較為缺乏堅持的意願，因此非自願的樞紐比起自願的樞紐較有可 能在兩翼的交叉壓力之下選擇一邊做結構性的傾斜。這就會改變戰略三角的整體 格局，將其由一個羅曼蒂克型三角轉變成婚姻型的三角。

　　　　　This paper examines the literature on strategic triangle and the pivotrole, compares German diplomacy under Otto von Bismarck of 1875-1890and the China policy of the US in the 1990s as two "unintending pivots," andanalyzes the cause of tilling between wings by unintending pivots. We findsated powers are more interested in a menage a trios than a romantic triangle.When such powers take the role of a pivot, the chances are that they are"unintending pivots." Secondly, for unintending pivots tilling between wingsis determined not by elite strategic thinking, but by domestic politics. In thecase of the US China policy, Washington's tilt towards either Taipei orBeijing is determined by the balance of power between idealism and realism,which in turn is synchronized with the presidential electoral cycles.Whenever presidential elections approach, or the opposition candidatedefeats the incumbent (or candidate from the incumbent party), then idealismsurges and Washington tilts towards Taipei. During the inter-election periods,however, realism rules and Washington tilts towards Beijing. Finally,compared with intending pivots, unintending pivots are less committed totheir role in the strategic triangle, and are more prone to make structural tiltstowards one wing, thus transforming a romantic triangle to a marriage.