In every U.S. presidential election, the major party candidates vie to see who can appear tougher on China. Once the election is over, however, the substance of U.S. policy toward China usually changes little and is far more pragmatic than the campaign rhetoric. There are ominous signs, though, that things could be different this time.

The accusations have been among the most caustic ever. Republican presidential nominee Mitt Romney has denounced the Obama administration for being “a near-supplicant to Beijing” on trade matters, human rights and security issues. An Obama ad accuses Romney of shipping U.S. jobs to China through his activities at the Bain Capital financier group, and Democrats charge that Romney as president would not protect U.S. firms from China’s depredations.

In large measure these jabs resemble a quadrennial political ritual. Ronald Reagan repeatedly criticized President Jimmy Carter for establishing diplomatic relations with Beijing. Bill Clinton excoriated the “butchers of Beijing” in the 1992 campaign and promised to stand up to the Chinese government on both trade and human rights issues. Candidate Barack Obama labeled President George W. Bush “a patsy” in dealing with China and promised to go “to the mat” over Beijing’s “unfair” trade practices.

Obama highlighted his decision to impose tariffs on Chinese tires in a recent campaign speech. The administration, he said, had decided to file two complaints with the World Trade Organization over Beijing’s allegedly illegal subsidies to China’s automobile industries. It was no coincidence that Obama announced this in Ohio, a battleground state where the auto parts industry is a major component of the economy.

Chinese leaders have learned to regard this quadrennial anti-China rhetoric with a mixture of patience and bemusement. They note that despite Clinton’s fiery comments, U.S.-China trade soared during his administration, and after the first year or so, criticism about Beijing’s human rights policies virtually disappeared. Bilateral relations during the Reagan administration were exceptionally good, as the two governments cooperated to contain the Soviet Union’s power.