The United States, Japan and 10 other Pacific Rim nations on Monday reached final agreement on the largest regional trade accord in history, teeing up what could be the toughest fight President Obama will face in his final year in office: securing approval from Congress...The Pacific accord would phase out thousands of import tariffs as well as other barriers to international trade, like Japanese regulations that keep out some American-made autos and trucks. It also would establish uniform rules on corporations’ intellectual property, and open the Internet even in communist Vietnam...Key members of Congress in both parties and interest groups influential in Washington expressed ambivalence at best or outright opposition, though the agreement’s 30-chapter text will not be available for perhaps a month.