Not sure about Canada specifically, maybe you could shed some light, but the US president has a lot more power than in a typical parlimentary system. This is typically why it’s seen as essential that they are voted in directly. Would the US be better under a parlimentary system? Very valid debate.
Kind of an interesting conundrum. What comes out in the trial will likely look bad on the US, mainly the tourture, but the plea deal could be a liability for the current admin, since they’d be accused of being soft on terrorism.
ETA: Plus more could come out about the security failures of 9/11 which could be pretty embarrassing to the US.