Being the son of former PM Pierre Trudeau, he wasn't exactly a neophyte that come out of nowhere.

Source: https://gamerant.com/times-games-supposedly-predicted-future-events/

It’s true that, under Pierre Trudeau, defence spending never exceeded 2.2 per cent of GDP.

Source: https://ottawacitizen.com/opinion/columnists/smol-was-pierre-trudeau-really-the-enemy-of-the-canadian-armed-forces

Perry’s mother served as press secretary to Trudeau's father, Pierre Trudeau, during his time as prime minister.

Source: https://www.kelownadailycourier.ca/entertainment/national_entertainment/article_8142c224-ce64-5f35-ace3-cd062777ab4b.html

Prime Minister Justin Trudeau has criticized the pre-emptive use of the provision and during a 2021 interview told The Canadian Press he shares the disdain his father, former prime minister Pierre Trudeau, had for its place in the charter.

Source: https://globalnews.ca/news/9496826/canada-notwithstanding-clause-exist-liberal-mp-debate/

Prime Minister Justin Trudeau has criticized the pre-emptive use of the provision and during a 2021 interview told The Canadian Press he shares the disdain his father, former prime minister Pierre Trudeau, had for its place in the Charter.

Source: https://www.baytoday.ca/national-news/time-in-canada-to-debate-whether-notwithstanding-clause-should-exist-says-liberal-mp-6577785