Washington policy makers are preparing plans to impose tariffs on some Chinese imports, limit Chinese investments in the United States, particularly in technology, and spend more on the United States military to sustain its big advantage over the People’s Liberation Army.

In congressional testimony earlier this month, the director of the F.B.I., Christopher Wray, described China as “not just a whole of government threat but a whole of society threat.”

Mr. Trump may well see Mr. Xi’s consolidation of power as part of a global trend toward increasingly influential leaders, in which he might include himself along with Mr. Xi and Vladimir V. Putin, the Russian leader, said James Mann, the author of “The China Fantasy,” which contradicted the popular view that increasing prosperity would lead to political liberalization in China.

“I’m guessing he will not deplore the lack of democracy in China, because that’s the sort of thing he rarely if ever does,” Mr. Mann said of Mr. Trump.

Mr. Mann also said Mr. Trump might not have much problem with what Mr. Xi had accomplished.

“Over the past 14 months in office, Trump has almost never voiced the sort of support for our constitutional system that has been a staple in the statements of past presidents,” Mr. Mann said. “He does not respect the dignity or integrity of political opponents. He does not express support for the independence of the courts or the freedom of the press.”

So if anything, he said, “I think Trump is probably jealous.”

From Clinton to Bush to Obama, the prevailing belief was engagement with China would make China more like the West.