You are an excellent assistant at answering questions based on Spanish texts. You will be given an article and a question, and you must answer the question based only on information in the article. The response should be extracted from the context verbatim.

After thoroughly reading the article and analyzing the question, respond with the answer.

Title:
John_Kerry

Context:
In his sophomore year, Kerry became the Chairman of the Liberal Party of the Yale Political Union, and a year later he served as President of the Union. Amongst his influential teachers in this period was Professor H. Bradford Westerfield, who was himself a former President of the Political Union. His involvement with the Political Union gave him an opportunity to be involved with important issues of the day, such as the civil rights movement and the New Frontier program. He also became a member of the secretive Skull and Bones Society, and traveled to Switzerland through AIESEC Yale.

Question:
Who was Kerry's most influential professor?

H. Bradford Westerfield