The anniversary of Nixon’s historic visit to China calls for somber reflection on the intervening four decades of U.S.-China relations. As Minxin Pei points out over at The Diplomat, Nixon’s “bold gamble” paid off for both parties, but one benefited infinitely more than the other. Without question, “China has gained far more than the United States from the Sino-American strategic relationship.”

Pei exhibits a nuanced understanding of the mutually beneficial relations enjoyed by Washington and Beijing since the Nixon visit—and of their imminent deterioration. Indeed, he posits that the fundamental discrepancy between American liberal democracy and China’s one-party state makes competition and, eventually, collision inevitable. Pei calls it the “clash of their political systems.” His words cannot fail to bring to mind another clash—Huntington’s much-maligned clash of civilizations.

The three pillars of U.S.-China relations, according to Pei, are security, economy and ideology. Slowly but surely, ideological clashes are undermining the other two pillars. In terms of security, Washington and Beijing have already become “quasi-competitors, instead of quasi-allies, each viewing the other as a potential threat.” The economic relationship between the two countries remains important, but Pei notes that “the political economies of a liberal democracy (which favors free competition) and an autocratic regime (which favors state control) are fundamentally at odds with each other.” It won’t be long until this third pillar falls.

Pei’s assessment is not an optimistic one, but it acknowledges the fundamental “trust deficit” between any two nominally allied countries that lack “enduring strategic trust, based on shared values and similar political institutions.” It presents an explanation for the deterioration in U.S.-China relations alternative and probably superior to that of the “American desire for containment of a rising power.” And perhaps most importantly, it raises questions about the durability of U.S. alliances with other countries that do not necessarily share American values—Saudi Arabia, for example—and encourages critical thought about how to maintain relationships that serve American interests even if they prove distasteful or difficult given American values. Overall, it’s a smart piece that opens the door to smart discussion.