The right-wing movement of the early 1930s culminated in Mäntsälä in 1932. A social democratic assembly at the Ohkola people’s house was interrupted on February 27th when over 400 men surrounded the building while firing shots into the air and ground.
This came as no surprise to District Chief Paavo Susitaival and Commander-in-Chief Lauri Malmberg, who had visited President Svinhufvud to discuss precautions. They had asked for a social democratic politician’s appearance to be banned, and the date of the event had been changed.
The attackers advanced to the local Civil Guard house, refusing to hand over any perpetrators. Lapua Movement secretary Artturi Vuorimaa emerged as the leader of the crowd and prepared a manifesto addressed to the President. The declaration emphasized opposition to red Marxism instead of hostility towards the state, calling for swift action to prevent a looming civil war.
On February 28th, the Lapua Movement headquarters decided to send men to Mäntsälä. As the order was relayed through the Civil Guards, the party was deployed in full uniform.
The Government soon realized the severity of the situation. Contingents were assigned to guard essential locations in the capital, and an arrest order was issued on the leadership of the Lapua Movement. In return, the movement announced a national mobilization. Civil Guard troops were called in by district, and those in Mäntsälä formed defensive clusters. Confrontations with the Army were to be strictly avoided.
Consensus on appropriate measures was difficult to reach. Military Commander Aarne Sihvo wanted to defeat the rebels. Civil Guard Commander-in-Chief Malmberg was reluctant to stand against the Guards and was in favour of the Government resigning. President Svinhufvud wanted to find a peaceful resolution to the crisis.
At the turn of March, the Government unsuccessfully attempted to detain the leadership of the movement in Hämeenlinna. Later in the day, Minister of Defence Jalo Lahdensuo read a presidential declaration over the radio, commanding the Guards to return to their home districts.
The dire situation urged the President to form a governmental crisis staff. The discordant group consisted of Malmberg, Sihvo, Lahdensuo, Deputy Governor of the capital region Hugo Österman, and Chief of General Staff Lennart Oesch. Dreading a clash between the Guards and the Army, Malmberg and his chief of staff Väinö Palojärvi wanted to resign. Svinhufvud refused their requests.
The President decided to personally make a speech. He implored the Guards to consider the future of the organization, saying there would be no repercussions for those who had not instigated rebellious activities and chose to swiftly return home.
Svinhufvud’s speech reached 200,000 citizens. The rebels had attempted to occupy the Lahti radio station, but messenger Aulis J. Alanen had eaten the notice on the way after deeming the order absurd.
On March 3rd, rebels seized central locations in Jyväskylä and dethroned the district chief. Their unsuccessful attempt at dismissing a provincial assembly endorsing the Government produced the only civilian casualty of the rebellion when frightened farmer Matti Jääskeläinen died of a heart attack.
On Friday the 4th, a delegation of the Mäntsälä forces visited the President to demand a change of government. The Army began to surround Mäntsälä, and Svinhufvud appointed Lieutenant Colonel Elja Rihtniemi from the Supreme Headquarters as the official negotiator.
Lapua leader Kustaa Latvala shot himself at Seinäjoki. His last words highlighted the lack of planning in the movement.
After negotiations with Rihtniemi through the 4th and 5th of March, the leaders of the Lapua Movement decided to put an end to the rebellion. The final entry in the Mäntsälä rebel diary read as follows: ”5.3.32. END” Minister of the Interior Arvo Manner suspended the movement on March 24th, and the ban was judicially ratified in May. The leaders of the rebellion were sentenced to probation.