It’s possible John Thompson could have been a great prime minister, but he didn’t live long enough to let anyone find out. His brief, cautious term accomplished very little.
Thompson had a long and diverse political career, and to this day is the only prime minister who held office in all three branches of the Canadian government (executive, legislative, and judicial) and all three levels (municipal, provincial, and federal). Starting off as a member of the Halifax school board, he would serve as a city councillor and provincial legislator before eventually becoming premier of Nova Scotia, and then a judge on the provincial supreme court. After Prime Minister John A. Macdonald (1815-1891) offered him the post of attorney general, Thompson upgraded to federal politics and was successfully elected to parliament as a Conservative in 1885. He would serve three terms.
Religion was a big deal in Canadian politics in those days, and the fact that Thompson had voluntarily converted to Catholicism in order to marry his Catholic girlfriend generated a lot of suspicion and bigotry inside his strongly Protestant political party. Though he had approved the execution of Catholic rebel leader Louis Riel (1844-1885) in his role as Macdonald’s attorney general, internal opposition to his Catholicism remained strong enough to prevent him from becoming the country’s new prime minister following Macdonald’s death in 1891. Only when the man who was picked, John Abbott (1821-1893), resigned a year later did Thompson get to be prime minister — largely because there was no other viable candidate.
It’s likely Thompson’s religion would have caused greater problems had his administration ruled for any significant length of time. But poor health ultimately spared him the controversy, and Thompson died of a heart attack while travelling in England just a few days into his second year in office.