This paper explains the functions of the Formosan Association for Public Affairs (FAPA), a grassroots advocacy organization that aim to promote US-Taiwan relations in the United States, including the process of approaching members of Congress, cultivating public awareness on issues, and introducing bills, and the strategy behind these movements. The paper also examines different factors contributing to a successful grassroots campaign launched by FAPA which ultimately led to the legislature of the Taiwan Travel Act (TTA). As the TTA was proposed four times throughout three different presidencies before it passed in the year 2018, I weigh the relevant factors to its success or failure by comparing the TTA campaigns at different times. I conclude that the ability to find friends in Congress to support bills and resolutions is always a critical determinant for a grassroots organization’s success, and FAPA has always been good at finding champions in Congress. Also, a campaign based on the target state’s own values and interest are more likely to succeed. FAPA has always been good at framing issues to align with US values and interests. The fundamental factors that changed over time and led to the ultimate success of the TTA campaign are the change of public opinions towards Taiwan and China and the change in US interests in US-China relations. This conclusion proves that the legislative process efficiently represents US interests and public opinions in the making of the TTA, not just the FAPA's interests or Taiwan's interests.