A solution for NASA's problem about paying the Russians for a seat aboard Soyuz
If expedition 13 is exclusively a Russian crew (because NASA would be banned from sending a US astronaut to ISS aboard Soyuz), then why not keep Bill Mc Arthur up there until the Shuttle comes to get him?
I even thought of keeping him 18 months (with no Shuttle dependancy) up there so that:
1) The US gets the time-spent-in-space-in-one-flight record back.
2) There's much more learned about space endurance for a Mars expedition.
3) The US doesn't need to change the law.
4) The Russians have one or even two seats freed for paying customers.
Krikalev did this in 1991 (ok , it wasn't for that long ).
Raoul