presidential blunders

What was Abraham Lincoln's biggest mistake? Cyberspace is filled with diverging views on this topic. Here's a few of them.

• Many people claim that Lincoln's biggest error was the selection of Andrew Johnson as his running mate. You can read about this on A. Lincoln Blog, Civil War Memory, and Civil Warriors.
• OEsheepdog's Blog takes the unique viewpoint that Lincoln was proven terribly wrong when he said that "the world will little note, nor long remember what we say here" in his Gettysburg Address.
• Philip Schoenberg says Lincoln's biggest blunder was playing a practical joke that could have cost him his life. Lincoln in a duel?
  
• Many people have the opinion that Lincoln's biggest blunder was his appointment of George B. McClellan as general in chief. Jame's McPherson holds this opinion.

The video below claims to feature every known photograph of Lincoln. (Photo by Alexander Gardner. Colorization by Bryan Eaton.)