The Star Spangled Banner is a pretty difficult song to perform.  You've got to have some range to do it properly.

You also need to know the words.

There are dozens of examples of screw-ups.  Carl LewisRoseanneThis girl.

As far as screw-ups go, James Taylor's flub before Game 2 of the World Series was small.  It could have been on purpose.

Taylor started to sing America The Beautiful.  Watch this clip.

Now, here is the whole thing.