At the heart of the current crisis between Washington and Moscow is this: President Vladimir Putin has massed troops on Russia's border with Ukraineand implied that he may invade unless he receives a guarantee that Ukraine will never join the North Atlantic Treaty Organisation (Nato).
The Biden administration rejects that demand out of hand. Powerful nations, it insists, cannot demand that their neighbours fall under their "spheres of influence".
As Secretary of State Antony Blinken put it last month:
"One country does not have the right to dictate the policies of another or to tell that country with whom it may associate; one country does not have the right to exert a sphere of influence. That notion should be relegated to the dustbin of history."
It's a noble principle, just not one the United States abides by.
The US has exercised a sphere of influence in its own hemisphere for almost 200 years, since president James Monroe, in his seventh annual message to Congress, declared that the country "should consider any attempt" by foreign powers "to extend their system to any portion of this hemisphere as dangerous to our peace and safety". Listening to Mr Blinken, you might think that the US long ago deposited this prerogative over the foreign policies of its southern neighbours in history's dustbin. It has done no such thing.
In 2018, president Donald Trump's secretary of state Rex Tillerson called the Monroe Doctrine "as relevant today as it was the day it was written". The following year, his national security adviser John Bolton boasted that "the Monroe Doctrine is alive and well".
To be sure, the US doesn't enforce the Monroe Doctrine in the same way it did in the first half of the 20th century, when it regularly deployed its Marines to Central America and the Caribbean, or during the Cold War, when the Central Intelligence Agency helped topple leftist governments.
Washington's methods have changed. It now prefers using economic coercion to punish governments that ally with adversaries and challenge its regional dominion.
Consider Washington's decades-long embargo on Cuba. US officials may claim the embargo's goal is to promote democracy, but virtually every other government on earth - democracies included - views it as an act of political bullying. Last year, the United Nations General Assembly condemned the embargo by a vote of 184 to 2. Human Rights Watch has denounced it for imposing "indiscriminate hardship on the Cuban population".
Biden officials do not celebrate the Monroe Doctrine as their Trump administration predecessors did. But they still muscle America's neighbours. President Joe Biden hasn't eased the embargo on Cuba. Nor has he ended Mr Trump's effort to cut off Venezuela, another autocratic government that flirts with America's foes, from global trade.
The US, in the words of one European Union official, is still prepared to "starve Venezuelans until their leadership surrender or their people oust them". These policies serve notice to other Latin American governments that defying Washington can bring grave costs.
The US also wields considerable influence through its "soft power". Because the US has a dynamic economy and an open society, close relations with Washington are more attractive to America's neighbours than close relations with Moscow are to Russia's.