My thought is that if Mexico preserves its current status as a multi-party state, while at the same time Low-Info US voters usher in an era of permanent one-party rule, including corruption going through the roof at all levels of govt, we just might reach the point where most attempted illegal border crossings finally flip to be a majority fleeing from north to south.
Canada will likely not be an enticing haven for US refugees at that point, because their transition to one-party rule will likely parallel ours, and happen even faster.