After the 2014 season, here is the ranking (folded teams included): Pos. Team: Total (D1 Cup - D1 Reg. Season - Nat. Cup) 1. NY Cosmos: 12 (5-7-0) T2. DC United: 11 (4-4-3) -. LA Galaxy: 11 (5-4-2) 4. Montreal Impact: 9 (0-0-9) 5. Chicago Fire: 6 (1-1-4) T6. Columbus Crew: 5 (1-3-1) - Seattle Sounders: 5 (0-1-4) - Sporting KC: 5 (2-1-2) - Maccabi LA: 5 (0-0-5) - Bethlehem Steel: 5 (0-0-5) T11. SJ Earthquakes: 4 (2-2-0) - Toronto: 4 (0-0-4) - NY Greek Americans: 4 (0-0-4) - Philadelphia Ukrainians: 4 (0-0-4) - Fall River Marksmen: 4 (0-0-4) source: http://en.wikipedia.org/wiki/List_of_American_and_Canadian_soccer_champions
This is a bit misleading as it does not include the league results for Fall River or Bethlehem Steel, both of whom played in the top division (ASL at the time) for at least part of their existence). The Soccer War makes it a bit hard to definitively give a number of titles, but Bethlehem Steel should have at least 1 regular season title (2 if you count their win in 1921 as the Philadelphia Field Club) while Fall River should have 8 regular season titles and 7 playoff titles.
I actually have put some thought on that, but I eventually decided against it. I am open for arguments, but that fact that those leagues seemed REGIONAL to me lead to disregard them as NATIONAL titles.
I think it is also misleading that you are using 2002-2007 Voyageurs Cup counting as the national cup of Canada. Between this period, it was not an individual tournament but a "competition" taking into account USL regular season match ups between Canadian clubs only. Several of this kind of competition still exist, namely Cascadia Cup, which has been awarded since 2004. I think it is wrong to elevate the status of the 2002-7 Voyageurs Cup over such cups because it involved the only professional teams of an individual nation. Furthermore, the 2007 Voyageurs Cup did not involve all professional clubs - Toronto FC was not taken into account as they did not play matches against USL Canadian clubs. In actual fact, "Open Canada Cup" operated as the national cup of Canada between 1998 and 2007. Although it was mainly entered by those who played entirely within the Canadian soccer pyramid, USL teams did occasionally enter.
On Open Canada Cup, it is not an issue here. Since no team has won it more than three times, accepting the tournament or not, no team would make the ranking.
My point here is that Canada Soccer Association accepted the trophy as the one given to Canada's National Champion when taking it as the official trophy for the National Championship. Since there is a continuation, I believe there is no reason to treat its champions differently.
2015 National Cups Champions: Canada – Vancouver Whitecaps FC USA – Sporting Kansas City Pos. Team: Total (D1 Cup - D1 Reg. Season - Nat. Cup) 1. NY Cosmos: 12 (5-7-0) T2. DC United: 11 (4-4-3) -. LA Galaxy: 11 (5-4-2) 4. Montreal Impact: 9 (0-0-9) T5. Chicago Fire: 6 (1-1-4) - Sporting KC: 6 (2-1-3) T7. Columbus Crew: 5 (1-3-1) - Seattle Sounders: 5 (0-1-4) - Maccabi LA: 5 (0-0-5) - Bethlehem Steel: 5 (0-0-5) T11. SJ Earthquakes: 4 (2-2-0) - Toronto: 4 (0-0-4) - NY Greek Americans: 4 (0-0-4) - Philadelphia Ukrainians: 4 (0-0-4) - Fall River Marksmen: 4 (0-0-4) -- Vancouver Whitecaps FC: 2 (1-0-1)
2015 D1 Regular Season Champions: MLS - NY Red Bulls 2015 D1 Cup Champions: MLS - Portland Timbers FC 2016 National Cups Champions: Canada – Toronto FC USA – FC Dallas 2016 D1 Regular Season Champions: MLS - FC Dallas -- Pos. Team: Total (D1 Cup - D1 Reg. Season - Nat. Cup) 1. NY Cosmos: 12 (5-7-0) T2. DC United: 11 (4-4-3) -. LA Galaxy: 11 (5-4-2) 4. Montreal Impact: 9 (0-0-9) T5. Chicago Fire: 6 (1-1-4) - Sporting KC: 6 (2-1-3) T7. Toronto: 5 (0-0-5) - Columbus Crew: 5 (1-3-1) - Seattle Sounders: 5 (0-1-4) - Maccabi LA: 5 (0-0-5) - Bethlehem Steel: 5 (0-0-5) T12. SJ Earthquakes: 4 (2-2-0) - NY Greek Americans: 4 (0-0-4) - Philadelphia Ukrainians: 4 (0-0-4) - Fall River Marksmen: 4 (0-0-4) -- FC Dallas: 3 (0-1-2) NY Red Bulls: 2 (0-2-0) Portland Timbers FC: 1 (1-0-0)