He is recognized as one of the leaders of the so-called Juanistas, a faction within Carlism pressing recognition of the Alfonsist claimant Don Juan de Borbón as a legitimate Carlist heir to the throne.

[2] One of its branches held large estates in Caparroso, in the Southern part of Navarre known as Ribera Aragón; in the early 19th century José Arellano y Ochoa was its alcalde and one of key figures.

[24] Luis is probably first noted as active within the public realm during the first electoral campaign of the Republic in 1931; engaged in Juventud Tradicionalista,[25] he kept delivering harangues in favor of Carlist candidates in small locations like Sangüesa in Eastern Navarre.

During the 1933 electoral campaign, Arellano was included as Carlist candidate on the Navarrese Union of the Right coalition;[29] he was comfortably elected with 72 thousand votes and together with José Luis Zamanillo became one of the youngest Traditionalist deputies ever.

[30] In great national politics Arellano followed Rodezno and his policy of seeking alliance within a broad monarchist grouping, first in coalition named as TYRE[31] and later having signed manifiesto constitutivo of Bloque Nacional;[32] he remained active in the latter despite discouragement from the emerging Carlist leader, Manuel Fal Conde.

[45] Arellano was heavily involved in conspiracy to overthrow the Republic; during the hectic July 1936 last-minute political negotiations between Carlist leadership and the army conspirators he sided against Fal and with the Rodeznistas, pressing almost unconditional support of the military.

[51] According to accounts available he acted as a liaison officer, travelling almost every day to Navarre and back until mid-August 1936,[52] when he assisted his sister and mother, released from prison in the Republican zone, to settle in Pamplona.

[57] When pressure on unification started to mount Arellano again sided with Rodezno;[58] by some scholars he is even considered co-leader of the Rodeznistas,[59] pressing compliance and advocating the Carlist entry into a new partido unico.

[63] Apparently he did not realize the terms of forthcoming amalgamation; in the last-minute attempt as representative of Carlist labor structure Obra Nacional Corporativa Arellano was delegated to negotiate unification conditions.

[64] In April 1937 Arellano formed part of the pressure group which visited the regent-claimant and Fal in Saint-Jean-de-Luz and presented them with sort of an ultimatum, forcing Don Javier and his jefe delegado into silence.

Though in the Carlist media Arellano was one of the faces of unification,[68] he was amazed by declared terms of the process; immediately following Decreto de Unificación he travelled to Franco to voice his disgust.

[71] Their relations with Don Javier remained extremely tense yet not broken;[72] it was only after in November 1937 Arellano had accepted seat in a 50-member Consejo Nacional[73] that the claimant declared him one of key rebels against his authority and expulsed them from Comunión Tradicionalista.

[74] Arellano together with López Bassa co-headed Comisión de Organización Sindical, set up by the Falangist Secretariato; the body was entrusted with drafting theoretical framework for labor organization in the new regime.

At this position Arellano pursued a Traditionalist corporative vision,[75] but he was confronted by hard-line Falangist members like Joaquín Miranda and Pedro González Bueno, who advanced their idea of sindicatos verticales.

[76] When in early 1938 Rodezno assumed Ministry of Justice in the first Francoist government, Arellano followed him as sub-secretary[77] - the post initially offered to José María Valiente, but rejected - and held it until the cabinet was reorganized and Rodezno replaced by Esteban Bilbao in August 1939; 70 years later this service cost him charge of committing crimes against humanity[78] He was getting increasingly disillusioned with the new party, trying to save what was left of Carlist assets and becoming shareholder of El Pensamiento Navarro, spared amalgamation by turning it into a commercial newspaper.

Little is known about Arellano's public activity in the 1940s; holding no official posts he remained an important figure in Navarrese political realm,[81] especially that his promoter Rodezno was at that time vice-president of Diputación Provincial.

Within Navarre he tried to counter the influence of Fal Conde by supporting the iconic local Baleztena family, generally loyal to Don Javier but displaying a fairly independent stand.

Though no longer member of Consejo Nacional, he was assured seat in the Cortes from the pool reserved for personal Franco's appointees; until mid-1960s he was not acknowledged as taking part in major legislative work or any related back-stage political haggling between different Francoist pressure groups.

[103] In 1960 he was involved in promoting so-called Fuero Recopilado de Navarra, a legislative attempt launched by Diputación Foral and aiming at consolidation of Navarrese civil code and its integration into the Spanish legal framework; he served as a liaison between the Navarros and Minister of Justice Iturmendi.

Following running of the bulls - with Don Carlos Hugo taking part in a carefully arranged publicity stunt – Arellano attended an evening cocktail party to honor the prince.

Still loyal to Don Juan and still member of his Private Council,[117] he was invited to major events in family of the Alfonsine claimant, like the 1967 wedding of his oldest daughter, Pilar de Borbón,[118] and especially to the 1968 christening of his first grandson, Felipé.