During the 60-80s, Italy lived a period of increasing political violence and terrorism, the so called [years of lead](http://en.wikipedia.org/wiki/Years_of_lead_(Italy)). There is a theory out there that states that some politicians, together with the Mafia, the Church Hierarchy and elements of NATO/CIA, made political use of terrorism ('strategia della tensione') to stop the rise of the Communist party, that at the time was the biggest in the West.
Some argue that this is only a lefty conspiracy theory.
Does anyone know if there are reliable proofs to this theory?
PS: To those who understand italian.
To be sure, the "anni di piombo" period is usually associated with left wing terrorism, of which the chronicles of the time are full. They culminated with the kidnapping and murder of Aldo Moro (at the time the head of the major christian democratic party) in 1978, and in the kidnapping and subsequent liberation of the US Army General James Dozier in 1982.
Both those kidnappings, and score of other killings, wounding, and other crimes were mainly done by an organization called the Red Brigades, and some other minor ones; those were certainly not a creation of politicians, the Mafia or the Catholic Church, but had their roots in the left wing movements that were born after the spring of 1968. Their targets were politicians, cops, journalists, judges and university professors. On the whole, the crimes of those organizations did not target the general populace.
There were also a number of bombings, killing a big number of civilians. The first was the bomb in Piazza Fontana in Milano, the most famous one is the bomb in Train station in Bologna.
For most of those bombings there have been not final convictions, so nobody is sure who did make them and why. Anyway, they are usually associated with right wings terrorists, some of which were long be suspected to be in contact with parts of the secret services, the italian ones or the CIA.
Anyway, no direct and provable link has really been found (at least in a judicial setting).