The Democratic Party was one of the original parties in Janda's 1950-1962 ICPP study. The party continued throughout 1950-1990 in the Harmel-Janda study of party change.

The essay on party politics in the United States from 1950 to 1962 says:

Although the Democrats controlled Congress (both House and Senate) for all but one session from 1950 through 1978, the party held the presidency only in 1950-1952 (Truman), 1961-1968 (Kennedy and Johnson), and 1977-1980 (Carter).

The essay on party politics in the United States from 1963 to 2000 says:

Since 1962, the Democrats won the presidency in four elections: 1964 (Johnson), 1976 (Carter), 1992, and 1996 (Clinton both times). Until the 1994 election, the Democrats thoroughly dominated Congress, controlling the House for 38 of 40 years from 1950 to 1994, and the Senate for 32 of the 40 years.

Consult the index to variables for annual scores of the party's issue orientation, organizational complexity, centralization of power, and coherence from 1950 through 1990.