It is. The project just became a waste of tax payer dollars if the station doesn't accomplish it's goal. To have to construct another one to properly and effectively set up bases on the moon and Mars is exactly the kind of pork-barrel spending that was mentioned that killed NASA in the first place.
It isn't the goal of the ISS to set up bases on Moon or Mars. Its goal is to conduct scientific experiments in an microgravity environment (which admittedly sounds far less sexy, but that's how it is).
Politically, the ISS had also the purpose of tying the Russian space program to the American one after the end of the Cold war.
Lets not pretend Mars wasn't on the table.
But before then, the multinational partnership overseeing how the ISS will be used discussed plans for missions that could extend beyond low earth orbit, with an eye toward Mars, the Moon, or to an asteroid.
That's not the first time either. My books dated 1990 that depict the full version of the ISS or Freedom and the Space Dock frame the Station as a crucial component for Mars transit and return for a low consumption voyage significantly cutting cost for the Mars and Moon Projects. I never said anything more than this..
The misconception is that I made some sort of statement on the ISS's Mission. Reiterating: prejudices against negative comments about NASA and the legitimacy of it's projects are usually not well received. But I give you credit for going further than Maxwell did not deriding what you didn't understand. That's how conversation works.