[2] Allen was elected as a judge of the Sixth Judicial District of Kansas in November 1890.
[2] He was defeated in a bid for re-election in 1891, but in 1892 was elected to a six-year term as a justice of the Kansas Supreme Court by the combined vote of Democrats and Populists, taking office in January 1893.
The majority of the court decided to take jurisdiction of the case, and held the Republican organization to be the legal one.
[2] Allen was nominated for reelection by both the Populist and Democratic conventions in 1898, but was defeated, along with the balance of the ticket in that election.
Pallbearers at his funeral included then-Chief Justice William Agnew Johnston, Justice Frank Doster, and federal judges George Thomas McDermott and Richard Joseph Hopkins.