What president was most closely associated with modern republicanism?

President Dwight D. Eisenhower is most closely associated with modern republicanism. His administration, which spanned from 1953 to 1961, emphasized a middle ground approach that blended traditional conservative values with some progressive policies, particularly in areas like infrastructure and social welfare. Eisenhower's "dynamic conservatism" aimed to balance government intervention with individual liberties, shaping the Republican Party's identity in the post-World War II era.