The life of William Lyon Mackenzie King, Canada’s longest-serving prime minister, has been a favourite topic of Canadian historians for decades. Yet first-time author Julie F. Gilmour has managed to break fresh ground with Trouble on Main Street, a look at King’s involvement in the aftermath of the 1907 Vancouver race riots. (A Labour Day weekend parade organized by a group opposed to Asian immigrants in the city turned violent, and threw a spotlight on controversies surrounding Canada’s immigration policies.)

An examination of King’s words and actions following the riots, Gilmour contends, tells us a lot about who he became as a man and politician. For example, while serving on the commission that evaluated damage to Japanese homes and businesses, King was praised for his balanced approach, listening to each plaintiff and using rational calculations to award compensation. Later, as prime minister, one of King’s greatest legacies was his ability to bring opposing sides together in compromises that avoided alienating either.

Gilmour also draws a direct line from the riots to King’s determination that Canada should speak with its own voice on the world stage. In 1907, the Canadian government was trapped between its status as a British colony that could not set its own immigration policy and a citizenry agitating for fewer “unassimilable” arrivals from Asia. The circuitous, behind-the-scenes route King had to take to settle Canada’s differences with Japan, China, and India convinced him that having diplomats on the ground overseas was key to ensuring his country’s interests were adequately recognized.

Trouble on Main Street tells a very interesting story about a topic that has not received much coverage. Gilmour has done a good job accessing diverse sources to get each side’s perspective, and skilfully conveys the diplomatic manoeuvering in a manner that is easy to follow. She does have a tendency to repeat herself, and the last chapters, which recount a succession of King’s meetings with foreign dignitaries in minute detail, become tedious. But the book remains a good read and a well-painted portrait of the development of both Canada as a country and King as its eventual leader.