[quote=The Nexerus]
Why did France surrender Alsace-Lorraine to the Germans? That area was carved out of France in the Franco-Prussian war, so it shouldn't even exist as a region yet, let alone be being given off to the German Confederation.
[/quote]

Because Prussia was unwilling to sign away the use of its prodigious army without precluding a very likely scenario in which it would have no other recourse but to employ it, namely, a scenario in which France or Denmark violates the rights of ethnic Germans.