What did the outcome of the 1948 presidential elections reveal apex?

The presidential elections of 1948 revealed the Democratic party as the largest party in the country.

The surprise of Truman's victory in 1948 was the fifth consecutive victory for the Democratic Party in the presidential election. As a result of the 1948 congressional election, Democrats regained control of the two houses of Congress. Thus, Truman's election confirmed the Democratic Party as status for most of the nation, a status it would maintain until 1952.

He was not elected to the office, but became president after the death of Roosevelt, who had been elected to his fourth term as president.