The latest in a spate of recent cases of restitution of stolen artworks has legal experts pondering: Nazi or Soviet expropriation, does it make any difference?

Following a ruling by the US Circuit Court of Appeals in New York, Vincent van Gogh’s 1888 oil painting ‘The Night Café’, which was expropriated by the Bolsheviks in 1918 will remain at Yale University Art Gallery.

The Russian Bolshevik revolutionary government stole the $200m (£131m) artwork together with Cézanne’s portrait of ‘Madame Cézanne in the Conservatory’ from their owner, the private Russian collector Ivan Abramovich Morozov, in a decree of 19 December 1918.

Both were sold by the Soviets in 1933 to American collector and founder of the Baseball Hall of Fame in Cooperstown, New York, Stephen Carlton Clark. Clark went on to bequeath the ‘The Night Café’ to his former college Yale and ‘Madame Cézanne’ to the Metropolitan Museum of Art where he served on the board.

Morozov’s great-grandson Pierre Konowaloff brought ownership claims against Yale and the Met but both have been barred by the ‘act of state’ doctrine. This judge-made rule holds that courts “will not examine the validity of a taking of property within its own territory by a foreign sovereign government, extant and recognised by this country at the time of suit” unless stated otherwise by a treaty.

The decision will come as a relief to Yale, which had argued that if Konowaloff’s claim succeeded, it could cast doubt on the ownership of tens of billions of dollars worth of artworks and valuables.

Responding to the judgment, Konowaloff’s lawyer Allan Gerson stated that his client had been denied an opportunity to provide evidence obtained from the Russian government:

“I have never seen such short shrift given to a serious argument… The history books will show that this was really a terrible decision.”

But why are the courts prepared to rule on ownership claims to artworks looted by the Nazis and not the Soviets? Where does the difference lie? Noah Feldman, columnist for Bloomberg and a professor of constitutional and international law at Harvard University has attempted to solve this conundrum:

“The legal answer turns out to be surprisingly convoluted. In essence, it’s this: The Nazis are different.”

This ‘difference’ was underscored by an act of the State Department in response to a 1947 ruling of the 2nd Circuit Court. The court had invoked the ‘act of state’ doctrine to bar a claim by Arnold Bernstein to his shipping line, which was confiscated by the Nazis. The judgment was reversed in 1954 after the State Department sent a letter to Bernstein’s lawyers which stated that it was “the policy of the Executive … to relieve American courts from any restraint upon the exercise of their jurisdiction to pass upon the validity of the acts of Nazi officials.”

Feldman suggests the executive branch of US government has concentrated all of its efforts on assisting heirs to valuables plundered by the Nazis and neglected to support victims of theft by the Soviet regime. To his mind, you cannot distinguish one kind of theft from another:

‘Either the courts should return government-stolen property, or they shouldn’t: The rules shouldn’t vary based on details that are hard to follow even for lawyers’.

‘The Night Café’ will be kept on public display at Yale University Art Gallery.