[4] Buchanan was appointed Minister without portfolio in Alexander Cameron Rutherford's government after the election, however he resigned his Cabinet position on March 8, 1910, over a disagreement with provincial railway policy resulting from the Alberta and Great Waterways Railway scandal, and later resigned his seat in the Legislature on September 20, 1911.

Buchanan was a strong believer in reciprocity, a policy of increasing trade with the United States led by Liberal Prime Minister Wilfrid Laurier.

[7] Buchanan was subsequently successful, and was elected for the seat of Medicine Hat as a federal Liberal defeating Conservative incumbent Charles Alexander Magrath by 1,355 votes.

[8] Despite Buchanan's success in Medicine Hat, the Liberal Party lost 48 seats and control of Parliament, and new Conservative government led by Robert Borden took charge.

He was re-elected to the House of Commons of Canada as a Unionist for the new riding of Lethbridge in the 1917 general election defeating Laurier Liberals opponent Lambert "L" Pack.

In 1918, Buchanan was part of a group of Canadian journalists brought over-seas to see the battlefields and military installations of the First World War as guests of Lord Beaverbrook, the head of the British wartime Ministry of Information.

[citation needed] A malignant growth was discovered in Buchanan's body sometime in August 1953 and he died on July 12, 1954, ten days after celebrating his 78th birthday.