Democrats.org:

One more example of the total disintegration of John McCain's presidential campaign:

McCain's support has collapsed in Iowa. His support among registered Republicans dropped from 14.4 percent in March to 1.8 percent in July-August.

And take a look at this:

UI political scientists note that McCain has been passed in popularity not only by former Sen. Fred Thompson, R-Tenn., who earned 5.2 percent support, but also by a Democratic challenger, Obama, who is supported by 6.7 percent of Republicans.

 Ouch.  When more than THREE TIMES the Republicans support Obama over you, that's gotta smart.