not all Germans supported the Nazis, in fact there was a plot to assassinate Hitler which very nearly was successful
http://en.wikipedia.org/wiki/20_July_plot
There were a number of plots to kill Hitler over the years, but I agree that this one came much closer to success than any of the others. Whether the conspirators had any real prospect of seizing power and bringing the war to an end is another discussion though.
It's also true that "not all Germans supported the Nazis" but post war denial has clouded the issue. It's difficult to assess, and remains controversial.