SOFIA, Bulgaria — There is something mystifying about the American obsession with Vladimir Putin’s Russia. The Kremlin’s annexation of the Crimean peninsula, its military involvement in Syria and its meddling in elections abroad may help explain some of America’s sense of alarm. But they fail to explain why liberals in the United States are so much more vexed by Russia than they are by, say, the growing economic power and geopolitical ambitions of China, or the global ideological challenge of radical Islam or the sheer craziness of a nuclear-armed North Korea.

Russia suffers from demographic decline and arrested modernization. Its economy is overdependent on exporting natural resources. Its population has one of the highest percentages of university-educated people but the lowest labor productivity in the industrialized world. And although Mr. Putin is a strong and ruthless leader who enjoys popular support at home and celebrity status abroad, Russia’s institutions are corrupt and dysfunctional: Russian bureaucrats spend much of their energy fighting one another over money and power and have no time to cooperate. And Russia’s future after Mr. Putin — whenever that may come — is anybody’s guess.

Was it not just two years ago that President Barack Obama called Russia a “regional power”? And is it not true that even today most experts concur that while Moscow is an aggressive military power interested in counterbalancing America’s influence in the world, it is no traditional “rising power”? As the eminent American historian Stephen Kotkin wrote last year in Foreign Affairs, “For half a millennium Russian foreign policy has been characterized by soaring ambitions that have exceeded the country’s capabilities.” It is no different today.

And yet despite all of this, Americans are mesmerized and terrified by Russia. Is it simply that for liberal America, “Russia” is a code name for “Donald Trump”?