Tom Dennison, known as Pickhandle or Old Grey Wolf, (October 26, 1858 – February 14, 1934) was an American political boss and racketeer in Omaha, Nebraska.

A politically savvy, culturally astute gambler, Dennison was in charge of the city's wide crime rings, including prostitution, gambling and bootlegging in the 1920s.

[6] Upon surveying the city, he found Omaha to be a "wide open town", meaning there was little legal control over gambling, liquor, prostitution and other criminal interests.

[2] In 1916 Nebraska passed a state constitutional amendment allowing for prohibition,[12] and in the late 1910s, Dennison's political power waned.

Omahans, fed up with Dennison's corrupt style, voted in Edward Parsons Smith, a reform-minded candidate committed to "cleaning up Omaha", as mayor in 1918.

[13] Boss Dennison nursed a grudge against Mayor Smith that is ultimately attributed with leading to the Omaha Race Riot of 1919.

That year the Omaha Bee newspaper, founded by Edward Rosewater in the previous century, luridly reported on fictitious assaults on white women by black men.

[14] This, along with economic conditions facing recent veterans returning from World War I, led to increased racial tension throughout Omaha.

On September 28, 1919, a white mob launched a riot resulting in the brutal lynching death of black civilian Will Brown, the death of two white rioters, the injuries of many Omaha Police Department officers and civilians (including the attempted hanging of Mayor Smith), and a public rampage that included the burning of the Douglas County Courthouse in downtown Omaha.

The riot "was not a casual affair; it was premeditated and planned by those secret and invisible forces that today are fighting you and the men who represent good government.

This led to violence among the city's bootleggers, culminating in the 1931 murder of Harry Lapidus, a local businessman and outspoken opponent of the Dennison machine.

A campaign by state officials, including several raids, drove several establishments underground; however, Dennison encouraged the transformation of the industry, leading saloons to become cocktail lounges and taverns.

In this same time frame Dennison also ran Omaha's Flatiron Building at 1722 St. Mary's Avenue as a refuge for mobsters running from the law in Kansas City, Chicago and St.

[19] Dennison's key lieutenant and business manager during Prohibition was local power broker William "Billy" Nesselhous, who ran most gambling operations, speakeasies and brothels in the city.

[24] Dennison was fictionalized as a character in two recent novels set during the machine era in Omaha: Kings of Broken Things (2017) by Theodore Wheeler and World, Chase Me Down (2017) by Andrew Hilleman.