After endorsing the UN Guiding Principles on business and human rights (UNGPs) in 2011, the UN began in 2014 work on a possible treaty on business and human rights. This brief explains the progression of legal reasoning around corporate human rights responsibilities during the last two decades. One can identify three stages, or “baselines”, that were drawn in the mid-2000s, in 2011, and post-2014 on how to regulate the activities of multinational enterprises (MNEs). The argument here is that the third legalization baseline should not instinctively revert to the first legalization baseline. Instead, it is imperative for the third legalization baseline to reflect a more complex regulatory understanding of legalizing the BHR field and use the leverage of multiple transnational policy channels to find new protective pathways.