Complex sentence: From 1932 to 1964, the Democratic Party was undoubtedly the majority party, winning seven out of nine presidential elections, and their agenda influenced policies undertaken by the Republican Eisenhower administration.
Split into simpler sentences: From 1932 to 1964, the Democratic Party was undoubtedly the majority party. During that time period, Democrats won seven out of nine presidential elections, and their agenda influenced policies undertaken by the Republican Eisenhower administration.