No weird answers, absurd answers, or links please :') According to Lincoln, what do the American people have to do to make sure that the U. S. soldiers who were killed at Gettysburg (and other battlefields) had not died "in vain"?

He wanted to make sure the men that sacrificed their lives for a cause, and that cause be a just one. He wanted to preserve the union at all cost, as well as give all men equality and liberties that they deserved. That was the cause he found necessary, and the cause our men rallied behind.

Thats what I think at least,

Hope it helps.

the answer would be logic.

a. the astrolabe could determine the correct latitudinal location of the ship