Robert Lighthizer was one of the early voices on unfair and imbalanced trade with other nations subsidizing their industry at the expense of American jobs in manufacturing long before DJT took up the issue in 2015-2016. Lighthizer as US Trade Representative negotiated the new USMCA that replaced NAFTA agreement for North American trade with Mexico and Canada.
Lighthizer was seeking a larger role than USTR, either Commerce or Treasury, yet he was reluctant to campaign for this or go to Mar-a-Lago to make his case. As a result says WSJ, he was passed over as Luttnick and Bessent tried to get DJT's attention. Another reason he was passed over is that DJT is sees the continuing flow of fentanyl and the migrant flows from Mexico, the sourcing from China, as serious issues that require using trade as part of the solution by 2024 if Mexico, Canada and China do not cooperate and hurt US interests.