Are Government's the ultimate authority for creating laws??

Government's are made up of humans--fallen beings. How can they be held responsible for creating the ultimate laws? From my Christian perspective, I know that God is the ultimate authority for creating law. Since man is sinful, he cannot even uphold the law, let alone be the ultimate law maker. The very fact man is sinful though makes it necessary that he is accountable for his actions here on earth. As John Locke stated, "Man is entitled to life, liberty, and property" within a true Democracy. Therefore, the government of a Democracy must make laws which enable man to keep that which he is entitled to. So while the government is accountable to its people (and God, though that part is often ignored) to make laws which preserve their rights, they are not the ultimate authority. Though Hitler declared it law to kill Jews, Nazi's after WWII were still convicted in trials despite the fact their government made it "a law." Just because a government makes a law, it does not necessarily make it correct. Further, back in early colonial American history, when African Americans could legally not vote, was that ultimately right? Obviously not! Likewise, how would laws be made if there was not a higher standard? How would our founding fathers just randomly come up with the idea of "freedom for all"? A higher being must have created ultimate laws because despite what the "government" may say, I know that killing innocent people, such as the Jews in WWII is wrong.