The German government marked the centenary of the Weimar Republic on Wednesday to mark the drafting of the country's first democratic but flawed constitution.

The document has long had a controversial legacy, as it was arguably one of the most liberal and progressive ever penned at the time. However, its weaknesses also aided Adolf Hitler in his rise to power in 1933.

German President Frank-Walter Steinmeier told centenary guests at Weimar's National Theater Wednesday that the constitution adopted in July 1919 was not only a "one-way street" into Hitler's Nazi "barbarity" that ended with the Holocaust.

"We should no longer view the Weimar Republic only from its end," said Germany's ceremonial head of state and former foreign minister.

Steinmeier was referring to February 6, 1919, just after World War I, as Germany's first post-monarchy National Assembly gathered and began deliberations on the key document for what became known as the Weimar Republic.

The document gets its name because German politicians gathered in the eastern city to craft it, although Berlin remained the capital of the newly-created republic.

Chancellor Angela Merkel told 800 guests at Wednesday's ceremony that "every generation must once again struggle for democracy," adding that present-day Europe had drawn on the lessons of Weimar and the "terrible" Nazi era.

Read more: The Weimar Republic, a pivotal era that's more than clichés

Stephan Harbarth, the vice-president of Germany's top court, said the anniversary was a "reason to celebrate." Speaking with the Rhein-Neckar-Zeitung daily, Harbath called the creation of the Weimar constitution a "turning point in German constitutional history," for its enshrinement of universal suffrage, religious tolerance, and freedom of expression.

Read more: Berlin - Metropolis of Crime 1918-33

Despite its shortcomings, Harbarth said it paved the way for the "brilliance of the Basic Law," the constitution that has ruled Germany since 1949.

Lessons from 'the failure of the Weimar Republic'

While the Weimar constitution was revolutionary for its day and paved the way for the first national German election in which women were allowed to vote.

But it also lent considerable power to the President, allowed for a suspension of rights under vague "emergency" powers, and without a threshold to enter parliament, allowed extreme splinter parties an outsized role in politics. All three of these failings were exploited by the Nazi party in one way or another during their rise to power.

"The failure of the Weimar Republic must, therefore, remind us…to counter those who seek to eliminate freedom and democracy, consistently and at an early stage," said Harbarth.

es,ipj/rc (dpa, AFP)