On February 28, the day after the fire, Hitler asked the elderly President Paul von Hindenburg to invoke Article 48 of the Weimar Constitution and sign the Reichstag Fire Decree. Hindenburg signed. The decree suspended habeas corpus, freedom of expression, freedom of the press, freedom of association, freedom of assembly, the privacy of the post and telephone. It authorized the central government to override the constitutional powers of the German states. The rights it suspended were never restored during Nazi rule. By the morning of March 1, the Prussian state police, now under Goring's control, were arresting Communists by the thousands. The first sweep took about four thousand. By the eve of the March 5 election, every Communist member of the Reichstag had been arrested or driven into hiding.

March 5, 1933, was supposed to be the election that finally gave the Nazis a clear majority. It did not. With the Communists banned and most of their voters intimidated, the Nazis still won only 43.9 percent of the vote. Their coalition partner, the German National People's Party, brought another 8 percent. That gave the Nazis 52 percent in the Reichstag, a majority but not the two-thirds needed to pass the Enabling Act, which would let Hitler rule by decree without parliamentary approval. So they made the two-thirds. Eighty-one Communist deputies, already under arrest or in flight, were prevented from taking their seats. Some Social Democrats were intimidated or detained. The Centre Party was persuaded to vote yes after Hitler made promises he had no intention of keeping. On March 23, 1933, the Enabling Act passed 444 to 94. Hitler had a legal dictatorship by lunchtime.

Marinus van der Lubbe maintained from his arrest until his execution that he had acted alone. Most historians since Fritz Tobias's 1960 reinvestigation have agreed: van der Lubbe was a pyromaniac with a documented history of setting buildings on fire in the days before February 27. The Nazis were not satisfied with one defendant. They tried van der Lubbe alongside four foreign Communists, the Bulgarian Comintern operatives Georgi Dimitrov, Vasil Tanev, and Blagoy Popov, and Ernst Torgler, the head of the German Communist Party. Dimitrov defended himself, refused court-appointed counsel, and used the trial as a platform to humiliate Hermann Goring on the witness stand. The court was forced to acquit all four foreign defendants in December 1933. Only van der Lubbe was convicted. He was beheaded by guillotine in Leipzig on January 10, 1934, three days before his twenty-fifth birthday. In 2008, under a 1998 law that voided Nazi-era convictions, the Federal Republic of Germany posthumously pardoned him.

The question still gets argued. The mainstream consensus, advanced by historians from Tobias to Ian Kershaw to Richard Evans, is that van der Lubbe acted alone and the Nazis simply got lucky and exploited the gift. Other historians have pointed to evidence that troubles the lone-arsonist account. Walter Gempp, the head of the Berlin fire department on the night of the fire, was dismissed weeks later for arguing that there had been deliberate delays in the response and that he had been forbidden to use his full resources. Gempp was imprisoned in 1937 and strangled in his cell on May 2, 1939. In 2019, a 1955 affidavit surfaced from a former SA man named Hans-Martin Lennings, who claimed his unit drove van der Lubbe to the Reichstag from an infirmary on the night of the fire and noticed the building was already burning when they arrived. The truth may not be recoverable. What is recoverable, what is not in serious dispute, is what Hitler did with the fire over the next twenty-eight days.

In the late 1930s, the German artist John Heartfield made a photomontage of Hermann Goring as a butcher in a bloody apron, the burning Reichstag at his back. The image is brutal and deliberately unsubtle. By then, the only people who could still publish such images were exiles. The Reichstag fire is studied now not really as a mystery, although it remains one, but as a case study in how a constitutional democracy can be dismantled in a month using its own emergency provisions. Article 48 was supposed to be a safety valve for genuine crises. In the wrong hands, with the right pretext, it became the legal mechanism for ending German constitutional government. The fire itself, whoever lit it, mattered less than what was waiting to be done with it.