 Complete the following phrase:  From the late 1960s until the early 1980s, the country experienced the Years of Lead, a period characterised by economic crisis especially after the 1973 oil crisis, widespread social conflicts and terrorist massacres carried out by opposing extremist groups, with the alleged involvement of US and Soviet intelligence. The Years of Lead culminated in the assassination of the Christian Democrat leader Aldo Moro in 1978 and the 