The routine rejection of these charges by the Iranian government is now accompanied by the statement that such allegations should be put before the trilateral security committee - consisting of Iraqi, American and Iranian diplomats - that was formed recently in Baghdad.
He then went on to welcome the involvement of Saudi Arabia to shore up Maliki's leadership, and possibly join the present trilateral security committee in Baghdad.
But a more realistic ambition is to establish new trilateral relations.
That is not his way: the Mexican president has come up with a plan to restore relations a trilateral security zone that would make Mexico and Canada the first line of defence of America's borders.With 300m crossings of the Mexico-United States border each year, a determined terrorist will always get through, say Mr Fox's aides.
A trilateral group of officials now meets regularly to swap notes.
The Franco-German duo that has habitually set the direction for Europe is widely resented, and the notion of adding Britain to form a trilateral group is little more popular (save in Britain).
But Shibley Telhami, a professor from Maryland University who serves on a trilateral American-Israeli-Palestinian committee, argues that an improvement in Syrian-Israeli relations could, in turn, work for better relations between Israelis and Palestinians.
Talking in Tokyo this week, for example, Takeshi Niinami, boss of Lawson, a huge convenience-store chain, argued both that Japan should join TPP talks as soon as possible and that TPP rules should be the basis for the trilateral discussions.
And some trilateral co-operation with America persists—over North Korea, for example.
Earlier this month police stopped participants from marching on Yangon, the largest city.The foreign ministers of China, Japan and South Korea met in Seoul for their first trilateral talks at such a level in three years.
The much-vaunted trilateral partnership between government, employers and unions works if the employer is an established large company; for a new or smaller one, it simply adds to costs.
