By Bruce Stokes, Director of Global Economic Attitudes, Pew Research Center

Special to CNN

What a difference a generation makes! Japan’s decision to join negotiations to create a Trans-Pacific Partnership with the United States and other Pacific nations reflects, in part, the sea change in public opinion that has transformed U.S.-Japan relations. A quarter of a century ago, ties between Washington and Tokyo were characterized by public distrust and animosity. Today, there is support for deeper integration of the two economies through greater trade. The upcoming TPP negotiations will be contentious. But the political context in which these talks will take place is far more supportive than ever before.

In the last few decades, despite periodic trade tensions, Americans have generally held a favorable overall opinion of Japan. In 1990, near the high point of  the Washington-Tokyo battles over trade in autos, rice and other goods, almost two-thirds of Americans nonetheless thought well of Japan, according to a survey by the Times Mirror Corporation. By 2009, 67 percent of Americans still felt favorably disposed toward Japan, according to the Pew Research Center.

But trade relations have long been a neuralgic irritant in bilateral relations. In 1989, 63 percent of Americans believed Japan practiced unfair trade, while a little more than half wanted to increase tariffs on products imported from Japan. In 1995, 61 percent of the American public approved of President Bill Clinton’s decision to impose import duties on imports of luxury Japanese cars.

But U.S. sentiment has shifted dramatically. According to a 2010 survey, three-in-five Americans now want to increase trade with Japan, compared with 58 percent who would like to deepen commercial ties with the European Union and only 45 percent who want to boost trade with China.

So why the change? One reason may be that China has replaced Japan as America’s principal trade competitor, both in fact and in the minds of the American people. In 1990, Japan accounted for 40.7 percent of the U.S. merchandise trade deficit. China made up just 10.3 percent. By 2012, Japan accounted for only 10.5 percent of the U.S. global imbalance. China was responsible for 43.3 percent.

It is little wonder then that today, four-in-ten Americans see China as the world’s leading economic power and thus the principal challenger to American economic preeminence. And according to a recent Pew Research survey, 49 percent of Americans want to be tough with Beijing on economic matters. By comparison, just 6 percent cite Japan as an economic powerhouse today, compared with almost half who thought Tokyo was the top dog in 1990.

The Japanese, for their part, have seen a markedly improved view of the United States. In 1993, only 37 percent of the public thought relations between Japan and the U.S. were good, according to a Yomiuri Shimbun survey. By 2002, almost three quarters had a favorable view of America, according to a Pew Research Center survey.

Japanese attitudes toward trade with the United State have also improved. In 1994, a United States Information Agency survey found that a plurality (40 percent) of Japanese thought that U.S. policies and actions were harmful to the Japanese economy. And more than half said Washington made it difficult to sell Japanese products in the American market. Today, 48 percent of Japanese think their country should participate in TPP, which is effectively a free trade agreement with the United States, according to a November 2012 Asahi Shimbun survey.

A more positive bilateral public disposition is no assurance of success for the TPP negotiations. Washington will want openings of the Japanese rice and auto markets that Tokyo will resist. As the talks become more acrimonious, public opinion on both sides of the Pacific could sour. But clearly these negotiations begin in a public opinion environment that is far more favorable than that which existed a generation ago. That, in itself, is notable.