The rebellion of July 1936 divided the three services tasked with Spain’s internal security, the rural gendarmerie of the Guardia Civil, the frontier guards of the Carabineros and the urban riot police of the Guardia de Asalto, as well as the local police forces of the towns and cities, almost in half. In some cases the decision of which side to support was by sheer circumstance of location, combined with self-preservation, while in others it was a conscious decision. Where a commander might choose a side, if his men disagreed with his choice, he might find himself arrested. In the case of the Civil Guard of Huelva, they pledged loyalty to the Government, only to go over to the Rebels after they had been dispatched to Seville to support the Republican militia there.
The security forces often bore the brunt of the initial fighting to determine which faction a locality would be held by, whether it was fighting against rebellious soldiers, or the local trade union militias. Where these forces sided with the government, they were mistrusted by the militias, as traditionally they were the forces that had been used to put down strikes and demonstrations.
All three forces only recruited ex-service personnel and in the case of the Guardia Civil and the Carabineros, actually had serving Army officers posted to command some units. As a result they were often more experienced and better trained than many Peninsular Regular Army units and almost on a par with some of the men in the African Army units. This made them a valuable commodity and ideal for spearheading assaults against less proficient forces. What they lacked however, except for the Assault Guards, were support and automatic weapons. To this end and particularly in the rebel forces, regular support units were detached from their own units and attached to support the operations of these forces.
As both sides settled down from the initial fighting, the security services were often grouped into ad hoc formations, either as almost entire battalions of one type, or mixed units containing men drawn from all of these services. As this occurred, the formations became more militarised in the process, eventually losing any individual identity, other than their unit titles. In other cases, there was still a need for their original functions to be performed and as the respective sides organized, some of these men were withdrawn from the fighting formations.
In the Republican areas, many former members of the disbanded army joined those units formed from the security services, to escape the suspicion and/or enmity towards them that was prevalent within many of the trade union militia units. As a result these units were often the strongest in terms of numbers and the most militarised of the Republican forces, outside of those units trained by the 5th Regiment.
In December 1936 the Cuerpo de Seguridad Interior (Internal Security Corps) was formed from members of all three services, but there were still identifiable units of security personnel in existence in the line, where they were routinely used as Batallones de Choque (‘Shock’ or ‘Assault’ Battalions) to spearhead advances, attacks and counter-attacks. By this point these forces had adopted the same organisation and had obtained all of the usual support weapons of any similar unit, other than their esprit de corps, they were little different in appearance to any other unit.
In the Nationalist Zone the role of the Assault Guards became somewhat redundant as the Falange was heavily involved in internal security and the pacification of the Rojos (Reds) in the rear areas. At the end of 1936, General Franco disbanded those units which had survived in the Nationalist Zone. For the Guardia Civil and Carabineros, other than some isolated instances, it was business as usual, apart from assisting the Falange in their morally dubious activities.
This list can be used to organise a platoon from any of the separate security services between July 1936 and around October-November 1936, when they either became indistinguishable from most other units, or returned to their peacetime roles. An Assault Guard unit is able to draw on its own integral support, while the Carabineros and Guardia Civil needed that support provided to them.
Outside of those units wholly composed of these forces, it was common to find groups of men from the other services fighting alongside them, either as additional sections, or even individual members or squads being incorporated within units which had taken losses.
In the Nationalist Zone, particularly in the first few weeks of the Civil War, mixed groups of Army of Africa, Falange and Security personnel, were dispatched to individual areas to root out Republican sympathisers, leading to clashes with small groups of militia on occasion. In the Republican Zone, the distrust of the security services often led to mixed groups being formed, by the expedient of adding a militia section to a security unit. Mutual trust within these groups could only develop over time.
All of these variations are possible using this list.
CoC – Security Services