> Wasn't the previous Canadian prime minister at least as xenophobic as Trump?

God no. They passed a (bullshit) law saying that they could revoke the Canadian citizenship of someone under specific circumstances. You had to be a dual citizen (or eligible?) and commit one of a few crimes.

- obtaining citizenship by fraud (this I think is entirely reasonable) - committing an act of terrorism - treason - taking up arms against Canada

The liberals repealed some of this already (IIRC everything but the portions about fraudulently obtaining citizenship).

> What will prevent Canadians from out-crazying the US in the next major election?

We have a sane electoral system and just generally aren't as crazy.