Petra Kelly

Often, the fields that are most badly scorched become the most fertile. The barren landscape of post-World War II Germany nourished radical new ideas that would take root not just there but across the Continent. One of the most significant of these was the notion that the political mainstream must concern itself with the environment.

Its passionate advocate was Petra Kelly, a native of Bavaria whose teenage and student years spent in the U.S. left her influenced by its civil-rights movement. She was always controversial, feminine and charismatic and a baby boomer at a time when...