Investor-state dispute settlement has reached a moment of reckoning. For a long time, SDS could present itself as a technical instrument of progress: protect investors, generate growth, and let the broader social good follow in time. That justificatory story has long sustained it, but it no longer commands assent. The politicisation of ISDS (its social contestation) reflects that deeper exhaustion. A regime designed to depoliticise investment disputes internationally has become the object of intense domestic salience and contestation, while efforts to restore legitimacy through technocratic reform have struggled to produce closure, to bring acceptance and calm. Drawing on theories of politicisation and on systems thinking, the paper explains why procedural or technical refinement cannot, under conditions of loud and noisy politics, drain accumulated distrust and disagreement. The problem lies deeper, in the growth-centred mental model through which the regime has understood its purpose and justified its consequences. The article therefore proposes a broader social acceptability function, centred on redistributed wealth, justice, security, and freedom to choose, as the basis for a credible depoliticisation, for a return to institutional calm.