Gave up.... Haven't the stomach now to wade through pages on Heidegger.... Maybe when I'm older.... The articles below (especially the one on E. Nolte), which are biographical and historical, are enough.
For an excellent brief and clear overview of the topic of Heidegger and his Nazi connections, see
Th. Sheehan, NYRB, vol. 35, no. 10 (1988): http://www.nybooks.com/articles/4397; also vol. 40, nos. 1&2 (1993) on Ernst Nolte: http://www.nybooks.com/articles/2701. For Wolin, who is an expert also on the Frankfurt School and on writers such as W. Benjamin, see The Seduction of Unreason:
The current book is a rich analysis of the philosophical basis, in Sein und Zeit, of Heidegger's political commitments and entanglements.