John George Diefenbaker
was a Canadian-born American politician well-known for his long and prolific career in American politics. Born in the town of Neustadt, Ontario, Canada, he and his family would emigrate to the American town of Tyler, Texas when he was three years old. The Diefenbaker family would become naturalized US citizens ten years later. After serving as a lawyer for much of his adult life, Diefenbaker ran for US House in 1938 as a member of the Freedom Party and won. He would be reelected twice, before being elected Governor of Texas in 1944. As governor, he would prove to be a close ally of President Earl Warren, supporting much of his war agenda. He would be reelected as governor in 1946, but resign in mid-1947 to become the very first White House Chief of Staff.
Diefenbaker would serve in this capacity until his election to the US Senate in 1948. As senator, he would go on to become one of the most influential and well-known senators of his generation, serving as Senate Minority Leader from 1955 to 1959 and then Majority Leader from 1959 to 1966. During his time in the Senate he would develop a rivalry with fellow Texas Senator Lyndon B. Johnson, who represented the Farmer-Labor Party. Diefenbaker would resign from the Senate in 1966 when President Nelson Rockefeller appointed him Secretary of the Interior, a position which he would hold until the end of Rockefeller's term.
Due to his political influence and name recognition, many in the Freedom Party wanted Diefenbaker to run for the presidency in 1968, although he was constitutionally unable to due to his status as a naturalized citizen. To get around this, a constitutional amendment was proposed to remove the natural-born requirement, although the amendment would be shot down due to the Farmer-Labor Party and many on the right-wing of the Freedom Party opposing it. Notably, future president Bob Dornan, who was then a young representative, was quoted as saying "hell will freeze over before I'll vote to let a Canuck into the White House."
Due to the failure of the amendment, the Freedom Party would instead nominate Vice President George W. Romney, who would go on to win the election. Romney would appoint Diefenbaker back to the position of Chief of Staff, a position which he would hold throughout the entirety of Romney's presidency. He would lose this position after Romney lost the 1972 election to Michigan governor Dominic Jacobetti.
Following the 1972 election, Diefenbaker would retire to his home in Tyler and pass away from a heart attack in 1979. His death made news headlines, with even President Jacobetti taking the time to speak fondly of Diefenbaker, something Jacobetti rarely did of Freedomites. Many consider Diefenbaker to be one of the "greatest presidents who never was". To this day the Freedom Party's federal headquarters are in the Diefenbaker Building in Washington, DC.
Credit for the idea of Texan Dief goes to @akagreenette