OK, so there is a bit of a circular firing squad going on in some of my R installs with ggplot2.  Apparently, you can get various CRAN/Github versions out of sync and a whole host of different.  Here is how it started:

hmmm….  Then ggmap also died.

To fix this, I did the following:

  1. Removed ggtern, ggplot2, and ggmap from my library
  2. Installed ggplot2 from CRAN
  3. Installed ggmap from GitHub
  4. Installed ggtern from Bitbucket (why not github, I don’t know).

Seems to work now.