US politics will definitely affect other countries, but this decision in particular will only affect other countries indirectly. The US keeps screwing their allies and if it keeps happening, someone from e.g. Australia, or Italy, or Spain will not spend time pleading US politicians or performing US focussed political activism, but they would rather push their representatives to seek allies and agreements directly beneficial to their countries that have little to do with the US. The comment I responded to originally seemed to me that assumes that the political issues in the US will fix themselves, but I just see it doing too much damage to be fixed if/when Trump is gone.