WordPress 3.2 upgrade, WYSIWYG editor no longer loads? Now requires JSON extension

An issue I encountered recently doing a WordPress upgrade from 3.1 to 3.2, is that afterwards everything appeared to work with the exception of the editor for Posts and Pages. After working through the checklist for the manual install and checking each plugin individually, I took a look at the PHP error log and noticed that PHP didn't have the JSON extension bundled.