The Liberal government could leave after only 90 days' notice, although it would still need to pay the remaining fees the Conservatives committed to the F-35 program
Linked National Post on purpose. Given their bias I believe they'd present the worst case scenario.
E: Apparently the article is from 2016 so the cost is likely higher today.
Why bother paying anything? Let it go to court. Threatening annexation should fall under some kind of hostilities clause, national security clause, or force majeure clause. Anyway who's going to collect?
The US government can pay MD Lockheed, they're the ones who threatened annexation.
Edit... Fixed above, not sure why I had MacDonell Douglas on my mind...strange substitution for a company that no longer exists under that name.
If it is mentioned, say "We have changed our course and will pay in full." Then don't pay. Wait a week and say "We changed course and won't pay." repeatedly flip flop like a Trump.