As a member of the conspiracy to destroy the dictatorship he often visited Madrid.

An uprising was planned for 24 June 1926, San Juan day.

He requested three days leave on 21 June 1926.

However, the "Sanjuanada" plot was discovered and on 23 June 1926 many of the participants were arrested.

The leaders, including Melquiades Álvarez and the Count of Romanones, were only fined.

General Weyler was acquitted and General Aguilera received a light sentence.

Colonel Segundo García was given eight years in prison, while Captain Galán and other officers were sentenced to six years in Barcelona.

While in San Francisco prison in Madrid, and then in Montjuïc Castle, Galán remained in contact with the movement opposed to the dictator and monarchy, and began to think about a combined civilian and military movement.

He made contact with some of the Catalan union leaders.

On 21 December 1926 he joined the Freemasons.

General Primo de Rivera was replaced by General Berenguer at the end of January 1930.

Berenguer gave an amnesty for the participants in the "Sanjuanada" plot.

Galán was released and at first lived in Barcelona, where he collaborated with workers' organizations and contributed to the socialist press.

He published Escribe Nueva Creación, an essay on political, economic and social doctrine that advocated a federal republican system.

The essay proposed that the community itself should administer wealth, and that Spain should be part of a United States of Europe.

Galán was assigned to Jaca in June 1930, an isolated posting where the authorities hoped he would not cause problems.

He still wanted to link a military uprising with the political movements opposed to the dictatorship.

He established contacts with the CNT in Zaragoza and Huesca, and started a close friendship with the syndicalist leader Ramón Acín of Huesca.

When the National Revolutionary Committee (CRN) was created in October 1930, Galán traveled to Madrid to meet the CRN leaders, and was appointed delegate of the CRN in Aragon.

From that time he mounted a campaign to get the CRN to support a military uprising at a national level combined with popular demonstrations, but was frustrated by constant postponements of the date.

Galán called the Executive Revolutionary Committee politicians the "telephoners", and did not want to rely on them to take action.

The date of 12 December 1930 was finally agreed, and then was postponed by the CRN to 15 December 1930.

The CRN representative Santiago Casares Quiroga knew of the decision to delay the uprising and came to Jaca late of the night of 11–12 December but did not notify Galán.

Casares thought Galán already knew of the delay, and that they could discuss the new plans any time the next day.

Quiroga, who was accompanied by Graco Marsá, took a room at the La Palma hotel instead of the Mur hotel where Galan was staying.

Marsá thought they should contact Galán, but Quiroga said he was tired out from the long journey and they should sleep first.
As a member of the conspiracy to destroy the dictatorship he often visited Madrid.
An uprising was planned for 24 June 1926, San Juan day.
He requested three days leave on 21 June 1926.
However, the "Sanjuanada" plot was discovered and on 23 June 1926 many of the participants were arrested.
The leaders, including Melquiades Álvarez and the Count of Romanones, were only fined.
General Weyler was acquitted and General Aguilera received a light sentence.
Colonel Segundo García was given eight years in prison, while Captain Galán and other officers were sentenced to six years in Barcelona.
While in San Francisco prison in Madrid, and then in Montjuïc Castle, Galán remained in contact with the movement opposed to the dictator and monarchy, and began to think about a combined civilian and military movement.
He made contact with some of the Catalan union leaders.
On 21 December 1926 he joined the Freemasons.
General Primo de Rivera was replaced by General Berenguer at the end of January 1930.
Berenguer gave an amnesty for the participants in the "Sanjuanada" plot.
Galán was released and at first lived in Barcelona, where he collaborated with workers' organizations and contributed to the socialist press.
He published Escribe Nueva Creación, an essay on political, economic and social doctrine that advocated a federal republican system.
The essay proposed that the community itself should administer wealth, and that Spain should be part of a United States of Europe.
Galán was assigned to Jaca in June 1930, an isolated posting where the authorities hoped he would not cause problems.
He still wanted to link a military uprising with the political movements opposed to the dictatorship.
He established contacts with the CNT in Zaragoza and Huesca, and started a close friendship with the syndicalist leader Ramón Acín of Huesca.
When the National Revolutionary Committee (CRN) was created in October 1930, Galán traveled to Madrid to meet the CRN leaders, and was appointed delegate of the CRN in Aragon.
From that time he mounted a campaign to get the CRN to support a military uprising at a national level combined with popular demonstrations, but was frustrated by constant postponements of the date.
Galán called the Executive Revolutionary Committee politicians the "telephoners", and did not want to rely on them to take action.
The date of 12 December 1930 was finally agreed, and then was postponed by the CRN to 15 December 1930.
The CRN representative Santiago Casares Quiroga knew of the decision to delay the uprising and came to Jaca late of the night of 11–12 December but did not notify Galán.
Casares thought Galán already knew of the delay, and that they could discuss the new plans any time the next day.
Quiroga, who was accompanied by Graco Marsá, took a room at the La Palma hotel instead of the Mur hotel where Galan was staying.
Marsá thought they should contact Galán, but Quiroga said he was tired out from the long journey and they should sleep first.
Fermín Galán