One of the biggest reasons this has been as effective as it has been is due to non-currency capital that was spent previously: soft power. The US has spent the last 70 years building that capital through aid and good will with partners around the world, and trading some of it back for advantageous deals in other sectors. Now, when their global impact is waning, particularly relative to China, he is spending that good will and partnerships built up over decades to extract concessions that would otherwise be considered untenable. And it will work, for a while. But it also means that countries will look to other trading partners rather than sticking with the no-longer-stable partnership with the US, such as the UK's auto industry in the video. The big problem is that soft power, good will to America, is being spent at a tremendous rate while also reducing the amount they build. When the piggy bank is empty, and all their partners have moved on, the dream of independence, which is in reality isolationism, will show its true consequences, a primarily internal economy and no cushioning or expanding effects of global trade. This will probably take longer than Trump being in power for the full effects to be seen, which is doubtless seen as a positive by Republicans. The real question is if it will be enough to make it impossible to support their military at current levels, and if they will then try to use that military to prop up their economy, as has been done elsewhere.