He was military commander of Berlin in the turbulent early days of the German Revolution of 1918–1919, and during the 1920 Kapp Putsch he was instrumental in organizing the general strike that helped defeat the anti-republican putschists.

Near the end of the Weimar Republic's life, however, he saw the futility of calling a general strike against the 1932 Prussian coup d'état because of the mass unemployment of the Great Depression.

After passage of the Act effectively gave Hitler dictatorial power, Wels fled the country and established the SPD exile organization Sopade.

The restaurant, which served as a meeting place for early SPD supporters, exposed Wels to the workers' movement at a young age.

On 9 November 1918, the date of the proclamation of the republic in Germany, Wels spoke to the Naumburg rifle brigade at their request to explain the political situation following the collapse of the German Empire at the end of World War I.

In December 1918, the Council of People's Deputies, Germany's temporary government, ordered the division to move outside Berlin and reduce the number of its soldiers.

[6] Assaults on the division's locations at the Berlin Palace and Neuer Marstall by regular troops loyal to the government – the 1918 Christmas crisis – failed to dislodge the mutineers.

Negotiations led to a compromise under which the Volksmarinedivision, in exchange for receiving its back pay and remaining a unit, vacated the Palace and Marstall and freed Wels, who was forced to step down from his position as city commander.

He played a key role in founding the paramilitary Iron Front and Reichsbanner Schwarz-Rot-Gold[8] in defence of Germany's parliamentary democracy against the rising extremist forces of the Nazi SA, Der Stahlhelm and the communist-led Rotfrontkämpferbund.

[9] In the July 1932 Prussian coup d'état, Chancellor Franz von Papen ousted the elected government of Prussia and took over control of Germany's largest state as Reich Commissioner, a move that was seen as a major blow to democracy in the Republic.

[1] Following the Reichstag election of November 1932 in which the Nazis lost seats, Wels rejected any negotiations with the new chancellor, Kurt von Schleicher.

Following the promulgation of the Reichstag Fire Decree on 28 February, Wels was threatened with arrest and fled with his family to Austria, but he returned in early March.

He went on to say that the SPD agreed with another statement of Hitler's, that "from the lunacy of the theory of eternal winners and losers came the madness of reparations and, in their wake, the catastrophe of the world economy".

However, that this attempt at defamation will one day redound back upon the instigators, that it is not our honor that is being destroyed by this global catastrophe, that is our belief to the last breath.Wels used Bauer's words in order to turn them against Hitler and the Nazis.

Nazi intimidation had worked so well that even if all 120 SPD deputies had been present and voted against it, the Enabling Act would have still passed with the required two-thirds majority for a constitutional amendment.

The passage of the Enabling Act marked the end of parliamentary democracy in Germany and formed the legal authority for Hitler's dictatorship.