alternatehistory.com

David Lewis came to Oxford University as a Rhodes Scholar in 1932. He soon took a leadership role in the university's socialist-labour circles and reinvigorated the Labour Club. In 1934 he became president of the Oxford Uniion.

When he graduated in 1935 he had a choice of two paths. The Labour Party offered him a safe seat in the House of Commons. According to wikipedia:
If he were to stay in England, he likely would have been a partner in a prominent London law firm associated with Stafford Cripps, and become a cabinet minister the next time Labour formed a government. Cripps then a prominent barrister and Labour Party official was grooming Lewis to be Prime Minister of the United Kingdom.

http://en.wikipedia.org/wiki/David_Lewis_(politician)

Instead he returned to Canada.

I am very surprised that the British Labour Party offered him a safe seat in 1935, when he was only 26 years old. One scenario is that he is elected as a Labour MP in a by-election sometime in the late 1930s. Churchill gives him a junior ministerial post in his wartime coalition government and Attlee appoints him to his cabinet when he becomes Prime Minister. He is promoted to Chancellor of the Exchequer when Cripps resigns in 1950. He is elected leader of the Labour Party when Attlee resigns in 1955.

If Labour win the 1959 general election he becomes Prime Minister. Otherwise he becomes Prime Minister when Labour wins the 1964 election. I am assuming that elections and other Prime Ministers are the same as in OTL.

What would he have been like as Prime Minister? How would his policies have differed from those of Harold Wilson? Would he have supported LBJ on Vietnam? I expect his post-humous reputation would be higher than Wilson's.

Also there would have been butterflies in Canadian politics. In OTL Lewis was elected leader of the New Democratic Party (NDP) in the fourth and final ballot in its leadership convention in 1971. James Laxer came second with 36.9% of the vote in the final ballot. But he was on the left-wing of the NDP so he probably polled his maximum support. So with no Lewis, John Paul Harney or Ed Broadbent, who came third and fourth respectively in the first leadership ballot, could have been elected leader, or someone else not on the ballot in OTL.

The butterflies could result in Jack Layton not being elected of the NDP. So who would be the most probable alternative leader instead of him?
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