Special Presidential Envoy for Climate John Kerry embarked this week on what he called a “constructive trip” to Europe, meeting leaders there before Secretary of State Antony Blinken had even packed a suitcase for his international debut as the United States’ most senior diplomat.Special Presidential Envoy for Climate John Kerry embarked this week on what he called a “constructive trip” to Europe, meeting leaders there before Secretary of State Antony Blinken had even packed a suitcase for his international debut as the United States’ most senior diplomat.