In February 1957, he was appointed Secretary-General of the "Movement"; a position that he would juggle with his role as the national trade union representative for more than a decade. He was known for being the least dogmatic member of the Falangist sector. Solís embarked on the task of modernizing the "movement".Within the party he collaborated closely with Fernando Herrero Tejedor, who was the Deputy Secretary General of the Movement during the 1960s. His appointment as chief of the FET y de las JONS came shortly after the so-called "Crisis of February 1956". Solís encountered an antiquated party, a victim of the separation between the generation that made the civil war and the younger generations. In a short time, he drew up the draft law of principles of the national movement, which sought to provide a legal basis for the single party of the regime and would end up being approved in 1958. However, some historians have considered that this law actually meant the beginning of the end of the FET y de las JONS as a party, diluting the nationalism within the "movement". Solís tried to assemble a nationalist project of an alternative regime to that of the Opus Dei technocrats. This project, which had already been partially employed in Labour Unions through an internal opening, was complemented by the creation of "associations" within the movement to equip the Franco regime with a certain level of popular participation in the so-called contrast of views. By October 1958 Solís had already created the National Delegation of Associations with the mission of "widening the bases of accession to the movement to collective groups" and to whose front he had appointed Manuel Fraga Iribarne. As Minister-Secretary General of the Movement, it was essential that the institutions of the Franco regime adapt to the social changes that were occurring in Spain, promoting a "political development" that complements economic growth. However, his association bill – which was already drawn up at the end of 1964 – was parked by the unmoving opposition of the Opus Dei technocrats, the undersecretary of President Luis Carrero Blanco and also by General Franco himself, with the fear that the "associations" could cause the reappearance of political parties. Solís continued to battle in this regard, and in the middle of 1969 he promoted a preliminary draft of the bases of the right of association, although again Franco did not