This is going to backfire on Trump and the US. By threatening, as the US has always done(with potential penalties of 100% tariffs) , even though past threats were carried out militarily or by assassinations, BRICS and other nations aren’t going to comply. Yes, they will obviously use dollars in their purchases of US goods, but they are not going to do so to transact between themselves.

If the US follows through on the 100% tariffs, the US economy will fall faster and farther because combined, all the BRICS and those wanting to join, produce, mine and manufacture just about anything they might currently get from the US. Talk about cutting off your nose to spite your face. The US is just going to accelerate the collapse of the dollar and the US economy.

On the other hand, if the US follows the plans about tax cuts, cutting spending and reducing govt. waste and fraud, that would help the US economy and the dollar and there would be less need for the rest of the world to flee the dollar. However that ship has sailed long ago. So while things could be turned around in the long term, the immediate future is the problem and Trump threatening the BRICS isn’t the solution.