WASHINGTON (Reuters) – Centrist Republican Richard Lugar, a soft-spoken foreign policy powerhouse who championed nuclear nonproliferation during 36 years in the U.S. Senate, died on Sunday at age 87.

The Lugar Center, a Washington-based nonprofit, said in a statement that he died peacefully at the Inova Fairfax Heart and Vascular Institute in Virginia due to complications from CIDP, a chronic neurological disorder.

Lugar, a professorial Midwesterner known for his keen intellect and mild demeanor, served eight years as mayor of Indianapolis starting in 1968 before his long stint in the Senate from 1977 to 2013. He was the longest-serving senator ever from Indiana.

Lugar was an influential Republican voice on foreign policy. A former Rhodes scholar and an avid runner into his 70s, Lugar served as chairman of the Senate Foreign Relations Committee and also headed the Agriculture Committee. He unsuccessfully sought the Republican presidential nomination in 1996.

Read the full story here.