Johnson signed the Outer Space Treaty, but that had absolutely nothing to do with the International Space Station.
Yes it did.
It established ‘international space law’, with the UN as the legislative and governing body.
Thus empowered, the UN then produced the ‘five declarations’ on outer space, one of which was the ‘international cooperation’ read wealth and technology redistribution, to poor countries who couldn’t afford to go to space, i.e. the international space station.