Rudi was responding under both NW and Passages to my post, so I should also repeat mine here in order to make sense.
With Cathay in OneWorld, Thai in Star, Malaysian Airlines [MH] has been left in the cold. Today Northwest Airlines and Malaysia Airlines announced an alliance that includes joint marketing and sales programs, coordinated scheduling and code-sharing. This month NW becomes the only US airline to serve Malaysia, and MH currently operates flights between LAX and Kuala Lumpur and between Newark and Kuala Lumpur. MH & NW are discussing reciprocal FF links and lounge access.
Looks like the third alliance is now really taking global shape, quite possibly further
downmarket than Oneworld and Star, ranked in that order, according to quality.
The puzzle is quite where SQ fits. By all international pax rankings it is head and
shoulders above the other Star carriers, and stands to compromise that reputation by merging its identity on many Star codeshare flights, especially those operated by TG & UA.
In retrospect inviting TG to be a member of Star was probably a mistake, as it has been severely hobbled by Thai military inteference, especially over acquisition of aircraft. The partial sale of TG has been discussed for years, but postponed again and again. When Star was formed, Asian economies were flourishing, and Singapore Airlines had no real interest in serious alliances. As the dominant party in its new tripartite relationship with Ansett and Air New Zealand, SQ must be drawn to Star -- but at what price?