When the Holy Roman Empire was dissolved in 1806, what had been since 1646 (after earlier privileges of autonomy of 1186) the Free Imperial City of Bremen was not mediatised.

But at the Congress of Vienna of 1815, Bremen's emissary, and later burgomaster, Johann Smidt, lobbied successfully to have the city's independence restored as one of the 39 sovereign states within the new German Confederation.

In January 1913, at the last elections to the Imperial Reichstag in Berlin, the Social Democrats (SPD) secured over half the vote, or 53.4%.

[5] Bremen, like all the German states, then underwent the process of Gleichschaltung (coordination) whereby the Nazi regime, through a campaign of violent demonstrations and intimidation, first forced the resignation of the executive Senate and later dissolved the Bürgerschaft.

Bremen remained for the next twelve years under the direct authority of a Reichsstatthalter (Reich Governor) who simultaneously held the post of Nazi Party Gauleiter of Gau Weser-Ems.

During these years, Bremen's small Jewish community (1,438 people registered at the beginning of 1933)[7] was destroyed through coerced emigration and deportation to death camps in the occupied east.

Allied bombing during World War II destroyed or severely damaged 60% of the city's built fabric, including much of its historic centre.

On a municipal level, the two cities in the state are administered separately: In post-war Bremen, the port, shipyards and related industries sustained a large and unionised working class.

However, in the 1980s mechanisation of the port and closure of the city's leading shipbuilder induced an employment crisis and shook the confidence of the party's traditional voter base.

Specialist construction yards, ship outfitters and parts suppliers remain, but AG Weser (which employed 16,000 workers at its peak) and Bremer Vulkan, Bremen's major shipbuilders, closed in 1983 and 1997 respectively.

Semi and unskilled harbour workers found it very difficult to re-enter the labour market, and unemployment—for a period in the 1980s almost double the West German average—remained comparatively high.

[15] With financial assistance from the European Union and the Federal Government of Germany, economic policy has focused on supporting those established economic sectors that are based on advanced technology, such as aerospace and aircraft production, automobile production, maritime and logistics services, and on developing the education and business-park infrastructure for new science-based and digital enterprises.

Several experts described Bremen's service sector as underdeveloped, due to a lack of major company headquarters.