The Globe and Mail reports in its Saturday edition that even if Prime Minister Justin Trudeau plays it as safe as possible on Monday when he meets with President Donald Trump, nothing is certain. The Globe's Adam Radwanski writes that Mr. Trump's one-on-ones with other heads of state seem to be all about unpleasant surprises. It is possible Canada has prepared more for the PM's interaction with Mr. Trump than has any other country. It is also anyone's guess how much that matters. By all accounts, Mr. Trump lacks interest in the detailed briefings that precede such meetings. He has a weak grasp of foreign relations more so than any modern U.S. president. Mr. Trump often reacts negatively when caught off guard by something he should have known about. Mr. Trudeau might try to account for that by playing it extremely safe, letting the President take the conversational lead as much as possible. Even then, there is no telling what might capture the President's attention and how he might act out. Maybe he will see an unflattering comparison with Mr. Trudeau on cable news and be defensive. The best-case scenario, from Ottawa's perspective, has to be as uneventful a Monday as possible.