Аннотация:Starting from the recent Philip Morris v. Uruguay Award, this Article tries to analyse the current status in investment arbitration of certain doctrines (and/or principles) which are adopted by arbitral tribunals in order to give due weight to state interests. The reference applies to the doctrines of the right to regulate and of the margin of appreciation as well as to the principle of proportionality. It will be argued that the right to regulate - which is today receiving growing attention by arbitrators, scholars and treaty drafters - still does not have the customary status which would entitle tribunals to apply it in the lack of a normative basis. Also the margin of appreciation, as technically developed by the European Court of Human Rights, cannot find a place in investor-State disputes, due to the very different framework in which arbitral tribunals operate if compared to the ECtHR. However, the principle of proportionality – being a general principle of international law – can perfectly offer to arbitrators a legal tool entitling them to pay due deference with regard to state sovereignty.
