Don't worry Convivial, the US military has lost every war it ever started in the last 214 years, starting with the War of 1812.
The last time the US tried to annex a foreign land and call it part of America was in fact the War of 1812, where the US tried 7 times and failed 7 times to annex what is now Canada. The British Army forced the US Army back south across the border despite the US having a military that was 10 times larger than the British Army.
Upon arriving back home in Washington DC with their tails between their legs and having several days to get their story straight before reporting back to the President, the US Army discovered the White House totally engulfed in flames upon their arrival home. The Brits had actually arrived there first and torched the US White House before the US Army made it back home.
Case in point, 9-11. Osama Bin Ladin showed the world how weak, unprepared and basically ineffective the US military really is and how totally inept the US government is at protecting it's own land.
The problem with the US military is that it too is inept, but inept at strategic planning and always has been. That is why the US came out the losers of Vietnam, Afghanistan and Panama just to name a few since 1958.
Therefore, be only afraid of what the global response will be if the US ever tries to pull that same arrogant stunt again with Canada or even Greenland.