I have an op-ed in the Sunday, June 12, 2010 copy of the Philadelphia Inquirer that essays a provisional answer to this question.
You may read the op-ed at http://www.philly.com/inquirer/opinion/.
It builds upon my previous blog posts on this question. Call it a further step in my nascent effort at political sociology on the Tea Party.
Please feel free to send me your comments and critiques.