The middle brother of the three sons of Pierre Trudeau is stepping up as senior adviser to big brother Justin's campaign for leadership of the Liberal Party.
Will he and Justin become Canada's Bobby and Jack Kennedy, surely the most famous of American political brothers? Even the ever-colourful George and Jeb can't displace them.
Justin chose the birthday of third Trudeau brother Michel, killed in an avalanche in 1998, to announce his run for the leadership, no doubt a way to include all three brothers in the momentous occasion.
So far, the debate has been over Justin's ability to step out from Pierre's shadow. Will having a brother as adviser help or hurt?
That would be hard to say. Sacha, a journalist and documentary filmmaker, has kept a relatively low profile up to now, so the Canadian public knows little about him. Even Wikipedia seems to have missed the birth of his third child. We do know he has said he has no interest in being involved in politics.
But longtime Trudeau family friend Jack Austin, a former B.C. senator, says the Trudeau boys had the best of groundings in public-policy matters and are well prepared for public life.
Canadians will be interested to see just how the Trudeau brothers story plays out.