Another Conservative-led coalition government. It's worse than that: the coalition was formed in Parliament years after the election-- though indeed the new arrangement was put to an electoral test right away.
By 1917 it had been six years since the previous election. The Liberals had agreed to a special one-year extension of the five-year parliamentary term in 1916, but not to Borden's request for an extension to last as long as the war did. With the breakup of the Liberals and the formation of the Union coalition government in 1917, Borden was ready to go.
The coalition was not caused by the war -- the Conservative Party had been content to rule alone from 1914 to 1917. It was conscription -- and the opportunity to rally English-Canadian Liberals to conscription and to seats in government, at the cost of isolating the Quebec Liberals. Given the passions of the war and the profound cultural conflict it created, it's probably not safe to generalize or draw analogies from the coalition election of 1917; it was pretty much a one-off.
A few new things: Borden's Conservatives had accepted a longstanding Liberal policy, and constituency boundaries were no longer set by gerrymandering governments but by an all-party committee -- the first step toward non--partisan electoral commissions.
1917 was the first federal election in which women voted. The provincial control of the federal franchise, re-established by Laurier in 1898, still prevailed. So women got the federal vote province by province: in 1917 women in BC, Alberta, Saskatchewan, Manitoba, and Ontario could vote in the federal election. (There was also a temporary federal vote-rigging amendment, that gave the vote to female relatives of serving soldiers, while taking it away from conscientious objectors).
One constant emphasized by John Duffy changed in the 1917 coalition election. Even in the big electoral sweeps of Macdonald and Laurier, total votes remained very evenly divided among the two parties: no election had ever given as much as 54% support to the winning party. The coalition election of 1917 changed that. The Union government got 57% of the vote and 153 seats in a 235-seat House; the remnant Liberals led by Laurier got only 40% and 82 seats. Jeez, today you can form a government with less than 40%
