The Trans-Pacific Partnership (TPP) is a potential free trade agreement (FTA) among 12, and perhaps more, countries ( Figure 1 ). The United States and 11 other countries of the Asia-Pacific region—Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore, and Vietnam—are negotiating the text of the FTA. With over 20 chapters under negotiation, the TPP partners envision the agreement to be "comprehensive and high-standard," in that they seek to eliminate tariffs and nontariff barriers to trade in goods, services, and agriculture, and to establish or expand rules on a wide range of issues including intellectual property rights, foreign direct investment, and other trade-related issues. They also strive to create a "21 st -century agreement" that addresses new and cross-cutting issues presented by an increasingly globalized economy. The TPP draws congressional interest on a number of fronts. Congress would have to approve implementing legislation for U.S. commitments under the agreement to enter into force. In addition, under long-established executive-legislative practice, the Administration notifies and consults with congressional leaders, before, during, and after trade agreements have been negotiated. Furthermore, the TPP will likely affect a range of sectors and regions of the U.S. economy of direct interest to Members of Congress and could influence the shape and path of U.S. trade policy for the foreseeable future. This report examines the issues related to the proposed TPP, the state and substance of the negotiations (to the degree that the information is publically available), the specific areas under negotiation, the policy and economic contexts in which the TPP would fit, and the issues for Congress that the TPP presents. The report will be revised and updated as events warrant. The Trans-Pacific Strategic Economic Partnership, as it was originally known, was conceived in 2003 by Singapore, New Zealand, and Chile as a path to trade liberalization in the Asia-Pacific region. Brunei joined negotiations in 2005, and the Trans-Pacific Strategic Economic Partnership (P-4) agreement was concluded in 2006. In March 2008, the United States joined the negotiations to conclude the still outstanding investment and financial services provisions. President Bush notified Congress of his intention to negotiate with the existing P-4 members on September 22, 2008, and with other countries, Australia, Peru, and Vietnam, on December 30, 2008. After a period of reflection on U.S. trade policy, the Obama Administration decided to continue with the TPP negotiations. On November 14, 2009, President Obama committed the United States to engage with the TPP countries "with the goal of shaping a regional agreement that will have broad-based membership and the high standards worthy of a 21 st -century trade agreement." President Obama formally notified Congress of his Administration's intention to enter into negotiations with the TPP countries on December 14, 2009. That notification set off a 90-day timeline under the now-expired 2002 trade promotion authority (TPA) legislation, for congressional consultations prior to the beginning of negotiations. In October 2010, TPP participants agreed by consensus to the inclusion of Malaysia as a negotiating partner. The negotiating partners announced a framework for the agreement at the sidelines of the Asia-Pacific Economic Cooperation (APEC) Ministerial in Honolulu, HI, November 8-13, 2011. Thereafter, Canada, Japan, and Mexico started to consult with the existing TPP partners on joining the negotiations. After several months of intense bilateral consultations with each of the current TPP countries, those countries agreed by consensus to the inclusion of Mexico and Canada and they began participating as negotiating partners in December 2012. Japan continued to debate internally the question of joining the negotiations, with Prime Minister Abe announcing Japan's official interest in March 2013. After concluding bilateral consultations, Japan began to fully participate in the TPP negotiations in July 2013. In early 2014, South Korea began consultations with the TPP negotiating partners over the possibility of joining, but at the time of this writing has yet to make a formal request to join the negotiations. It remains unclear whether the current 12 partners would permit another country's participation before concluding the initial agreement, although the United States seems to favor waiting until the current negotiations are completed. There is as yet no formal limit to the potential membership of the TPP, aside from excluding those countries unwilling to commit to the ambition of the proposed FTA. All current members of the TPP negotiations are also members of APEC, and the TPP countries have stated that membership expansion will likely focus on other APEC members first, such as South Korea, though non-APEC countries with a focus on trade liberalization, such as Colombia and Costa Rica, have also expressed an interest in joining TPP. The TPP negotiations remain ongoing through informal rounds, as well meetings among the chief negotiators and trade ministers. Both TPP leaders and ministers met on the sidelines of the November 2014 APEC meetings, but no major breakthrough was announced. A TPP Leaders statement following the meetings largely reiterated previous announcements, highlighting continued progress, and stating that "with the end coming into focus, we have instructed our ministers and negotiators to make concluding this agreement a top priority." The most recent negotiating session occurred in Hawaii during March 9-13, 2015. Prior to this round, an Australian negotiator claimed that 9 chapters had been completed: competitiveness and business facilitation, cooperation and capacity building, cross-border trade in services, customs, development, regulatory coherence, small and medium enterprises, telecommunications and temporary entry. Congressional consideration of Trade Promotion Authority (see text box below) could have significant implications for the conclusion of the TPP negotiations. Although the outstanding issues may be relatively limited, these issues are also likely the most challenging. The scope of tariff and agricultural quota removal or market access on sensitive products, particularly agricultural goods, as well as provisions over nontariff issues such as intellectual property rights, the environment, state-owned enterprises, and investment are reportedly among the most contentious unresolved issues. The United States' bilateral market access negotiations with Japan have been challenging as Japan seeks to maintain import protections for several categories of sensitive agriculture products and the United States seeks to address concerns over nontariff barriers in the Japanese auto market. As the two largest TPP economies, these bilateral talks have significant implications for the broader 12-country TPP negotiations and the timing of their conclusion. If completed as intended, the proposed TPP agreement would strengthen and deepen trade and investment ties among its participants. However, it may also have implications in larger, strategic contexts beyond the immediate participants: for U.S. trade policy in general; for the emerging trade architecture in the Asia-Pacific; for the multilateral trade regime within the WTO; and for U.S strategic interests in the Asia-Pacific region. The Obama Administration has argued that the strategic value of a potential TPP agreement parallels its economic value: TPP is as important strategically as it is economically. Economically, TPP would bind together a group that represents 40 percent of global GDP and about a third of world trade. Strategically, TPP is the avenue through which the United States, working with nearly a dozen other countries (and another half dozen waiting in the wings), is playing a leading role in writing the [trade] rules of the road for a critical region in flux. President Obama reiterated the strategic significance of the TPP negotiations during his State of the Union address to the 114 th Congress, arguing that the United States would benefit from developing the region's trade rules as opposed to other regional actors, namely China. The centerpiece of our economic rebalancing is the Trans-Pacific Partnership (TPP)-a high-standard agreement the United States is crafting with Asia-Pacific economies from Chile and Peru to New Zealand and Singapore. [ ... ] We always envisioned the TPP as a growing platform for regional economic integration. –Thomas Donilon, U.S. National Security Adviser, March 11, 2013 . The TPP has potential implications beyond U.S. economic interests in the Asia-Pacific. The region is increasingly seen as being of vital strategic importance to the United States. Throughout the post-World War II period, the region has served as an anchor of U.S. strategic relationships, first in the containment of communism and more recently as a counterweight to the rise of China. This trend has recently been accentuated by the Obama Administration's "pivot to Asia," along with the perception that the center of gravity of U.S. foreign, economic, and military policy is shifting to the Asia-Pacific region. The TPP is viewed as an important element in the U.S. "rebalancing" toward Asia. U.S. participation in TPP negotiations serves several strategic goals in U.S. trade policy. First, it continues and expands a U.S. trade policy strategy that began with the North American Free Trade Agreement (NAFTA), which entered into force in 1994, of using FTAs to promote trade liberalization and potentially to spark multilateral negotiations in the World Trade Organization (WTO). The George W. Bush Administration expanded the use of this strategy under the rubric of "competitive liberalization," negotiating 11 FTAs with 16 countries. The last three of these FTAs—with Colombia, Panama, and South Korea—were approved by Congress in 2011. However, the future direction of this policy was uncertain, given the low commercial value of some of these agreements and lack of new obvious partner countries. Meanwhile, an increasing web of bilateral and regional FTAs, were being concluded among other parties in the Asia-Pacific region and worldwide. The Bush Administration's and, then, the Obama Administration's support for negotiating a TPP agreement signaled that the United States remains engaged in regional free trade negotiations.