The next day, the Darmstadt Workers' and Soldiers' Council responded by declaring that the monarchy was abolished and entrusting Carl Ulrich, the leader of the Social Democratic Party (SDP) in Hesse, with the task of forming a government.

Although the republic had been unilaterally declared by the Workers' and Soldiers' Council, Carl Ulrich was a strong supporter of representative democracy.

[1] On 10 December 1918, the Ordinance for the election of a constitutional convention for the Republic of Hesse was published[2] in the Hessian government's gazette, along with some basic laws, drafted by Carl Ulrich.

In accordance with the Treaty of Versailles, approximately 40% of the state's territory (in particular, Rhine Hesse and part of Starkenburg) was occupied by the French Army from January 1919 until June 30, 1930.

[3] The state constitution came into force on 20 March 1920, and Ulrich continued in office as State-President (German: Staatspräsident).

After celebrating his 75th birthday in office in 1928, Ulrich retired and was succeeded as State-President by fellow Social Democrat Bernhard Adelung.

In the November 1931 elections, Adelung's coalition suffered a severe loss, winning only 37.1% of the vote (SDP: 21.4%, Centre: 14.3%; DDP: 1.4%[4]).

After the Nazi victory in the March 1933 federal election, they strongly demanded control of the State government.

Finally, on 20 September 1933, Sprenger forced Werner to retire as Minister-President and appointed Philipp Wilhelm Jung in his place, who bore only the title of State Minister (Staatsminister).

Hesse ceased to possess independence and was henceforth a legal subject (Rechtssubjekt) of the central government, without the status of a state (Staatscharakter), though formally it remained a self-governing unit.

of the constitution, the Landtag consisted of seventy members, who were elected by proportional representation for a three year term.

[10] The tasks of the Landtag were: legislating, passing a budget, electing the Minister-president ("Staatspräsident"), and confirming the selection of ministers.

Under Article 37 of the Hessian constitution, the Minister-President had the title of State-President ("Staatspräsident") and the cabinet was known as the "Entire Ministry" ("Gesamtministerium").

After that, the state government's functions were mostly taken over by the regional branch of the Nazi Party, Gau Hesse-Nassau, which also controlled the neighbouring Nassau province of Prussia, and the position of Minister-President was held by the Gauleiter from 1935.

At the same time, the cities of Darmstadt, Giessen, Mainz, Offenbach am Main, and Worms were made independent Stadtkreise ("urban districts").