Did Abraham Lincoln make any bad decisions?

Since Abe was human, it is safe to assume he made mistakes.

Seriously though, any answer to the question is largely a display of the personal judgment and values of the person answering it. In my opinion Lincoln made several mistakes 1) he underestimated how effective the Southern forces would be in the early battles, 2) he chose some of the wrong generals to lead Union forces, 3) he failed to take into account how much of a target he would be for those who supported the cause of the South (which is why his assassin was able to sneak into his box and shoot him). He may also have made a mistake in choosing his vice presidential running mate for his second election. He may also have missed an opportunity to integrate the forces of the union (placing blacks and whites into some of the same military units) or seeing to it that some blacks wer promoted into officer positions. Kind of hard to judge from our perspective now how those choices might have effected the war and subsequent history.

He dreamed four days before his death that he was going to die and DID know he was a target. He was told to be careful and not go, but replied: "I am going to die" he knew it was going to happen and that he would get assassinated so he went knowing it would happen sooner or later, so he didn't fail to take in account how much of a target he would be for southern supporters; he knew it was coming and took it in the face.