Only because the Great White North doesn't have an aircraft carrier and is safely protected under the US umbrella. But be careful because when that NK fat boy fires off his nuke his aim might be a little off and hit Vancouver instead of Seattle.
WimanND,
I spent a couple minutes to put a realistic war scenario together in which Canada was attacked by Russia, and had no U.S. help. Let's say for the sake of this scenario, Russia was at the point of economic collapse and desperately needed Canada's vast resources and Putin went full crazy person and decided to sail and fly across the Bearing Strait in attempt to invade Canada mere months from now. In this scenario, let's say the United States chose to be an isolationist (the reason is not important) and lend no support to Canada, as long as the Russians inflicted no damage, in any way, inside U.S. territory. So no deterrence against Russia (i.e. help for Canada from our American neighbours)... No "umbrella" protection. Also, this is a conventional war because we all know if one country nukes another, shit is hitting the fan... So lets watch this play out.
Admiral Kuznetsov and her fleet are deployed into the North Atlantic and attack Western Canada with the help of the Russian submarine fleet and their long range bombers from the airforce. Canada's western navy and airforce are overwhelmed and Western Canada is under a full fledged seige as Russia prepares to land thousands of soldiers and all of their support personnel into British Columbia, as well as paratroopers into Alberta and the Yukon.
In response, Canada immediately draws a line at Winnipeg, to defend the Central and Eastern portions of the country. 2/3 of Canada's military are located in the central and Eastern parts of the country. All elements are mobilized and thousands of reservists are called into duty.
At the same time, NATO's emergency reaction force is mobilized in Europe and begins to head West across the Atlantic for support. Simultaneously, The British Prime Minister, and his counterparts in France, Australia, Japan, etc, etc immediately declare war on Russia and support for Canada. Within hours hundreds of British, Australian, South African and Kiwi SAS commandos are in the air, headed for Canada, as well as well as French commandos, South Korean SEALS, Japanese Tokushusakusengun and Israeli Sayaret. They'll join Canada's JTF-2 operatives in what will turn into a shadow war vs Russian Spetznaz. They'll outnumber (and out specialize) the Russians some 15-1.
Shortly thereafter, HMS Queen Elizabeth and her battle group, supported by every other element of the Royal Navy will prepare to leave Portsmouth, and head towards waters in the North Atlantic. Their armada will be joined on route by Dutch and Norwegian destroyers and frigates as as our northern European friends prepare to return the favour Canada did them in liberating them during WW2. Their airforces, would join the RAF, along with those of Denmark's, Sweden's and Finland's to fly overhead cover.
A 2nd fleet of carriers Charles De Gaulle (France), Cavour (Italy) and Juan Carlos (Spain) and their accompanying warships would make way North East, through the English Channel, where they would pick up additional British Naval elements to form a massive armada, heading towards Russia, through the Bearing Strait and towards Admiral Kuznetsov.
A third fleet would leave anchor from their ports as the heads of state in Tokyo, Sydney and Auckland sent a combined fleet across the Pacific to pincer the lone Russian carrier and to combat the Russian southern fleet along the way. They would pick up their air support from Japan, South Korea and later the Turks as they made their way up towards coastal Europe. Russia would be spread incredibly thin.
Meanwhile, thousands of British Royal Marines and Aussie and Kiwi army units would prepare to depart to support the Canadian Army on the ground.
We all know how important air superiority is in modern war theaters. The Russians would undoubtedly have it early on, but as the F-18's of RCAF rallied in eastern Canada, they'd soon be joined by hundreds of British Tornado and Typhoon, French Mirage and Rafale, Spanish F-18's and Eurofighters, Italian Eurofighters and F-35's, and Eurofighters and Tornadoes of the Luftwaffe... Their new temporary homes would be every available airfield (of which there are hundreds in Eastern and Central Canada.
That would just be the first few days... I like our chances, even without our U.S. friends.