This report, updated as warranted, discusses U.S. security assistance to Taiwan, or Republic of China (ROC), including policy issues for Congress and legislation. The Taiwan Relations Act (TRA), P.L. 96-8, has governed U.S. arms sales to Taiwan since 1979, when the United States recognized the People's Republic of China (PRC) instead of the ROC. Two other relevant parts of the "one China" policy are the August 17, 1982, U.S.-PRC Joint Communique and the "Six Assurances" made to Taiwan. U.S. arms sales to Taiwan have been significant. In addition, the United States has expanded military ties with Taiwan after the PRC's missile firings in 1995-1996. However, there is no defense treaty or alliance with Taiwan. At the U.S.-Taiwan arms sales talks on April 24, 2001, President George W. Bush approved for possible sale diesel-electric submarines, P-3 anti-submarine warfare (ASW) aircraft (linked to the submarine sale), four decommissioned U.S. Kidd-class destroyers, and other items. Bush also deferred decisions on Aegisequipped destroyers and other items, while denying other requests. Since then, attention has turned to Taiwan, where the military, civilian officials, and legislators from competing political parties have debated contentious issues about how much to spend on defense and which U.S. weapons systems to acquire, despite the increasing threat (including a missile buildup) from the People's Liberation Army (PLA), as described in the Pentagon's reports to Congress on PRC military power. In February 2003, the Administration pointed Taiwan to three priorities for defense: command and control, missile defense, and ASW. Some in the United States increasingly have questioned Taiwan's seriousness about its self-defense, level of defense spending, and protection of secrets. The Pentagon also has shifted its focus from Taiwan's Special Budget to its regular defense budget and raising readiness for self-defense. Blocked by the opposition-controlled legislature, the Special Budget for submarines, P-3C ASW aircraft, and PAC-3 missile defense systems had been reduced from about US$18 billion in 2004 to US$9 billion (for submarines only) in December 2005. Then, in March 2006, Taiwan's defense minister decided to request a Supplemental Budget for the 2006 defense budget in part for submarine procurement, P-3Cs, and PAC-2 upgrades (not new PAC-3 missiles). Now, U.S. policymakers and firms are waiting to see how Taiwan's legislators might resolve the pending U.S. arms sales and increase spending in the 2007 defense budget during their fall session. Several policy issues are of concern to Congress for legislation, oversight, or other action. One issue concerns the effectiveness of the Administration in applying leverage to improve Taiwan's self-defense as well as to maintain peace and stability. Another issue is the role of Congress in determining security assistance, defense commitments, or policy reviews. A third issue concerns whether trends in the Taiwan Strait are stabilizing or destabilizing and how the Administration's management of policy has affected these trends. The fundamental issue is whether the United States would go to war with China and how conflict might be prevented. On June 29, the House passed H.R. 5672 with Sec. 801 to relax restrictions on senior military visits to and other contacts with Taiwan, but the Senate's version does not have the language. Also, in conference, the House receded from its sections boosting ties to Taiwan in the FY2007 National Defense Authorization Act (P.L. 109-364). [ABSTRACT FROM AUTHOR]