While the hardware will be different and the context will be different too, the space station gives a good institutional example of how to organize a trip to Mars. In the ideal world, it would be good if all partners at the time of agreement had stable, long-term commitments to their program. But these are political activities which can t guarantee stability. The big problem of the station in 1980s and 1990s was insufficient political will leading to the insufficient budget commitments. So, one hopes that if there is a commitment to a next large scale step, it would be accompanied by adequate resources.
Many people criticize the decision to have Russia responsible for a critical part of the station.
One has to be very conscious of how to organize a large scale long-term endeavor. Russia was put in the critical path of space station for primarily geopolitical and security reasons and, secondarily, programmatic reasons. But Russia had merited that place by its past achievements in long-duration spaceflight. And the U.S. agreed with that. The U.S. is not free to do anything it wants, if it wants real partnerships in space.