Why did the north fight to preserve the union during the civil war?

Question: Why did the north fight to preserve the union during the civil war!?
Best Answer - Chosen by Asker:

Because with the union preserved as one country, you had a superpower, which has been proven time and again in the last 150 years!.

If they had let the Confederate states secede and form their own union, it would have lefte both countries weaker, and possibly led to mor balkanisation and further wars!.

What Lincoln did may have trampled the constitution flat, but it sure helped the US be strong!.Www@QuestionHome@Com

Because to have an enemy so close was a terrible thought!. Yes there's canada & mexico but they weren't seen as hostile!. also the north was industrialized, so the raw goods (cotton etc) came from the south!.
America had agreed to abolish slavery as we were seen as cruel and barbaric to continue to use people as possessions!. Which could effect our relations & trading with other countries!. To have the south succeed would have undermined our president & nation!.
While we are taught at a very young age that the civil war was fought mainly to free the slaves, that simply isn't true!. There were many factors that brought us to war, which you should be learning in high school!.
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The south seceded and to not fight for the union, to not fight to preserve our country as a whole, a divided country would have been weaker!.Www@QuestionHome@Com

Why not!?

Preservation of the Union was essential to the continuation of the country!.Www@QuestionHome@Com

Hmm well I only done little study about the American civil war (i'm guessing)

and the civil war was fought to free black slaves from the south

or so it was told so balck soldiers would fightWww@QuestionHome@Com

Actually they were fighting to save the Onion, but Abe Lincoln was pickled at the time!.Www@QuestionHome@Com