why do USA will not unify with Canada?

Question

and then with Mexico and whole America and then Australia Japan Korea Taiwan Europe Turkey and will invade Russia and China and do Atomic war and then CHina Russia will unify with India and then with "Ak-kabiiru-Arabiyya "(country made by Bin Laden unifying all Muslim coutries (invaded with cold blood) ) and then with big Kongo Empire (which contains the most African coutries)
and then big war and then UFO will came and will say :
oh! I see you have big fun!

Answer 1

The War of 1812 was one of the goals which was not met. This is because the Land Victories of the British Army.

Answer 2

You started, at least, with a serious question. During the War of 1812 one of the goals of the USA was to take control of Canada. There were battles fought at Montreal and Quebec but not to a good outcome for the USA. That was the end of that. Did you know Canada is larger than the USA in square miles but has a total population smaller than that of California?

The USA did take control of Mexico after the war with Mexico ending in 1848. We chose to not annex Mexico, mostly because people were afraid it would become more land for slavery. There have been serious suggestions recently to the point where the USA and Mexico should combine. This would the illegal alien issue and would support the Mexican economy which is in terrible shape right now.

And the UFO fleets could come after that ...