Iran offered the US a package of concessions in 2003, but it was rejected, a senior former US official has told the BBC's Newsnight programme.
Tehran proposed ending support for Lebanese and Palestinian militant groups and helping to stabilise Iraq following the US-led invasion.
Offers, including making its nuclear programme more transparent, were conditional on the US ending hostility.
But Vice-President Dick Cheney's office rejected the plan, the official said.
But heaven forbid we actually made a friend over there. You never know when another enemy might come in handy to distract the American public, like now. A diplomatic initiative like this one could form a basis for understanding between two hostile nations. But understanding is the last thing this administration wants.