The special prosecutor, Lawrence Walsh, said he had had to contend with 'lies' and obstruction to produce his 566-page report on the scandal, which was unmasked in 1986. He concludes that senior members of President Reagan's cabinet systematically withheld information to conceal their chief's role in the affair.
Mr Walsh said a central theme of the report is that Iran-Contra was not 'a rogue operation' that went wrong but one that was planned and conducted at the highest levels. At the time, the scandal seriously weakened President Reagan's administration and continued to haunt President Bush right up to the final moments of the 1992 election. Although Mr Bush insisted he was 'out of the loop', notes taken at the time by the defence secretary of the day, Caspar Weinberger, shows him attending meetings about Iranian arms sales and financing the right-wing Contra rebels.
Mr Walsh's investigation was hampered by a competing investigation by Congress, which granted immunity to various participants in the affair, such as Colonel Oliver North. They then either escaped prosecution or had their cases dismissed on appeal. Mr Walsh noted yesterday that Congress had not even summoned either President Reagan or President Bush to give evidence but had blamed junior officials for 'a runaway conspiracy'.
The key conclusions of the report are that President Reagan had authorised his aides to defy Congress and secretly arm the US-backed Contra rebels in Nicaragua. He also authorised the sale of arms to Iran, although he had been warned this might be illegal. When these two plans were unmasked President Reagan 'knowingly participated or at least acquiesced' in a cover-up.
When President Bush, in his last days in office in 1992, pardoned all remaining government officials involved in Iran-Contra, Mr Walsh denounced it as part of a continuing cover-up. In his report he says that from the beginning, highly relevant documents 'were systematically and wilfully withheld from investigators by several Reagan administration officials'. President Bush refused to give up his diary and Mr Weinberger kept his rough notes of meetings.
President Reagan denounced the report yesterday as consisting of 'baseless accusations' that could not be proved in court. He said it was an expensive pat-on-the-back for Mr Walsh. Republicans have repeatedly said Mr Walsh was vindictively hunting down public officials who thought they were doing their job. Up to the last minute President Reagan's lawyers tried to prevent the report being made public.