-Quebec secedes in mid/late 70s
-Atlantic provinces (Newfoundland, Nova Scotia, PEI, and New Brunswick) decide to join US as feasible communication with Ottawa is difficult at best [this was apparently planned OTL should Quebec have seceded]. US gets control of Grand Banks and begins to eye Greenland for possible purchase.
For a bit more...
-Alberta oil wealth is explored/developed earlier and, in the eyes of Albertans, disproportionately used to the benefit of other provinces. "Secession or Union" becomes a battle cry within the province in increasing numbers
-British Columbia anounces that should Alberta gain independence in a referendum in 2010 that it will consider joining the United States. Yukon Territory soon follows with a similar announcement.
-Alberta secedes in 2010, joining the United States shortly thereafter. British Columbia and the Yukon Territory follow soon after.
-2011: Canada decides to apply for membership in the United States
-2012: Quebec goes bankrupt, negotiates with United States for possible admission as special status area hoping to be akin to Puerto Rico
Yes, a bit of a Yank-wank, but maybe the most plausbile for PODs in recent times