George Sinclair's 2007 article on the origin of the drink quotes the New York Herald Tribune from 1948: The mule was born in Manhattan but "stalled" on the West Coast for the duration.

That was back in 1941 when the first carload of Jack Morgan's Cock 'n' Bull ginger beer was railing over the plains to give New Yorkers a happy surprise…The Violette Family helped.

As Jack Morgan tells it, "We three were quaffing a slug, nibbling an hors d'oeuvre and shoving toward inventive genius".

Martin and Kunett had their minds on their vodka and wondered what would happen if a two-ounce shot joined with Morgan's ginger beer and the squeeze of a lemon.

Four or five days later the mixture was christened the Moscow mule...[7]Mayo Methot's husband, Percy T. Morgan,[8] an oil tycoon, was a co-owner of the Cock n' Bull restaurant.

In this story the cocktail's inventor was Wes Price, getting the idea from Hudes Potache, Morgan's head bartender and the drink was born out of a need to clear the bar's cellar, packed with unsold inventory, including vodka and ginger beer.

Martin asked bartenders to pose with a specialty copper mug and a bottle of Smirnoff vodka, and took Polaroid photographs of them.

The other photo was put into a collection and used as proof to the next bar Martin visited of the popularity of the Moscow mule.

In his book Beat the Dealer (1964), Edward O. Thorp did not name the Tahoe casino where he thought he had been poorly treated as a card counter.