I think this fits into a wider framework of political terrorism in 1970s Italy. The topic is, predictably, complex and contentious.

Kidnappings in 1970s Italy, while certainly not ordinary events, were nonetheless increasing with alarming frequency over the course of the decade. As the economic boom of the 1950s petered out over the course of the 1960s, by the recessionary '70s the country was beset by stark inequalities which prompted widespread resentment. While Il Boom had brought modernity to millions of people, millions more continued to live in agricultural poverty. Especially in the south, frustrations were augmented by the awareness that relatives and neighbors who had answered the call for factory jobs in big cities enjoyed modern amenities that those who had stayed home could not afford (most typically, people would travel from the south to the north for better paying jobs, but many southern cities also dramatically changed). The growth of mass media, including newspapers, film, and television increased awareness about this inequality. So while some kidnappings were meticulously planned, holding up celebrities and socialites, other times locals would hold up anyone driving a fancy car over mountain backroads in poorer and more isolated regions like Calabria and Sardegna. Before long, a "Kidnappings" section was added to the country's daily newspapers.

But, as political extremism would demonstrate, times were not happy in the prosperous cities either. While the "first" generation of new workers experienced a standard of living much higher than their parents', the generation of workers that entered the workplace starting in the late 60s saw cuts in industrial production due to a global recession. Problems were augmented as the Middle Eastern Oil Crisis created more economic uncertainty and dis-incentivized investment. The Italian government's solution was largely to organize hiring drives in state-sponsored businesses (through the finance ministry's holding company, the IRI, and the finance ministry's investment bank, the IMI, the Italian government could influence an enormous portion of the economy). However, this conflation of business with politics only fostered political radicalization. Radicalization was made even more appealing to disgruntled workers by the fact that in 1976 the country's two largest parties, the Communist Party and the Christian Democracy Party, reached a "Historic Compromise" to collaborate in the legislature (although the Christian Democrats, in power since 1946, continued to exclude the Communists from the executive). With the Communists and Christians working together, and business and politics increasingly one and the same, faith in authority figures of all kinds reached an all-time low, driven by a sentiment that all of the country's major decisions were taken by a shrinking group of individuals. Radical extremists on both the left and the right emerged carrying out politically motivated bombings, murders, and kidnappings, in the hopes of irreparably damaging the country's political and social order.

Aldo Moro, leader of the left-leaning current within the Christian Democracy Party who had acted as major sponsor of the "Historic Compromise," operated during the complex time in Italy's history which I just described: Inequality, kidnappings, and political violence were serious issues on which the country's two major political parties had converged to try to solve. While Moro's kidnapping and murder was a catastrophic failure of Italian institutions, he was not the first nor was he the last victim of extremist terrorism in Italy.

The social and economic unrest in Italy had led to the spontaneous creation of many individual radical cells working against the established social order. Some were violent, many were not. Although they might sometimes act in concert, most of the time contacts between them were haphazard and sporadic. Even within the same cell, there could be disagreements, challenges to leadership, and rogue agents. These characteristics would plague Moro's kidnappers, as would be made abundantly clear in the near-decade of investigations where investigators would arrest, try, and convict nearly every member of the Red Brigade cell that executed Moro's kidnapping and murder.

It is true that hypotheses of conspiracy were circulated by the press almost immediately after Moro's lifeless body was found. However, these speculations generally targeted Moro's rivals within Christian Democracy Party and their influence within the country's police and secret services. Over the years, theories have circulated involving everyone between Palestinian terrorists, the Soviet Union, and of course the United States. Certainly, Moro's longstanding position pushing for Christian-Communist collaboration made him an unpopular figure in American political circles. Further, Moro's standing within his own party put him in frequent contact with lawmakers in the United States, often creating difficult political situations and leading to frustration for Moro's more filo-American allies.

However, and here we get to the crux of your question, absolutely no opportunity for contact between the Red Brigades and the American intelligence services has ever been proven. The only hypothesis which investigators have found pursuable is that pressure by the United States intelligence service on their Italian counterparts to adopt a negotiation strategy, rather than stage a risky extraction. However, this hypothesis rests on the assumption that the Italian internal intelligence knew where Moro was being held; something that has been denied repeatedly.