It's all about NORAD. Why we need a multi role fighter to provide for NORAD though, I'm not sure. The likelihood of Canada employing a ground attack aircraft like that seems pretty unlikely.
As for the C-17 (and the Chinook, I might add), it looks like it's doing a pretty good job as employed now. The C130J will also be a great upgrade from where we are now.
So, looking at the success of those sole source purchases, why not new F-18s?
