a Member considers that any benefits accruing to it directly or indirectly under the covered agreements are being impaired by measures taken by another Member is essential to the effective functioning of the WTO".34 The fact that a Member may initiate a WTO dispute whenever it considers that "any benefits accruing to [that Member] are being impaired by measures taken by another Member" implies that that Member is entitled to a ruling by a WTO panel.
A decision by a panel to decline to exercise validly established jurisdiction would seem to "diminish" the right of a complaining Member to "seek the redress of a violation of obligations" within the meaning of Article 23 of the DSU, and to bring a dispute pursuant to Article 3.3 of the DSU. This would not be consistent with a panel's obligations under Articles 3.2 and 19.2 of the DSU.35We see no reason, therefore, to disagree with the Panel's statement that a WTO panel "would seem … not to be in a position to choose freely whether or not to exercise its jurisdiction."36
Mindful of the precise scope of Mexico's appeal37, we express no view as to whether there may be other circumstances in which legal impediments could exist that would preclude a panel from ruling on the merits of the claims that are before it. In the present case, Mexico argues that the United States' claims under Article III of the GATT 1994 are inextricably linked to a broader dispute38, and that only a NAFTA panel could resolve the dispute as a whole.39 Nevertheless, Mexico does not take issue with the Panel's finding that "neither the subject matter nor the respective positions of the parties are identical in the dispute under the NAFTA ... and the dispute before us."40 Mexico also stated that it could not identify a legal basis that would allow it to raise, in a WTO dispute settlement proceeding, the market access claims it is pursuing under the NAFTA.41 It is furthermore undisputed that no NAFTA panel as yet has decided the "broader dispute" to which Mexico has alluded. Finally, we note that Mexico has expressly stated that the so-called "exclusion clause" of Article 2005.6 of the NAFTA42 had not been "exercised".43 We do not express any view on whether a legal impediment to the exercise of a panel's jurisdiction would exist in the event that features such as those mentioned above were present.44 In any event, we see no legal impediments applicable in this case.
Finally, as we understand it, Mexico's position is that the "applicability" of its WTO obligations towards the United States would be "call[ed] into question"45 as a result of the United States having prevented Mexico, by an illegal act (namely, the alleged refusal by the United States to nominate panelists to the NAFTA panel), from having recourse to the NAFTA dispute settlement mechanism to resolve a bilateral dispute between Mexico and the United States regarding trade in sweeteners.46 Specifically, Mexico refers to the ruling of the Permanent Court of International Justice (the "PCIJ") in the Factory at Chorzów case, and "calls into question the 'applicability' of its WTO obligations towards the United States in the context of this dispute".47
Mexico's arguments, as well as its reliance on the ruling in Factory at Chorzów,is misplaced. Even assuming, arguendo, that the legal principle reflected in the passage referred to by Mexico is applicable within the WTO dispute settlement system, we note that this would entail a determination whether the United States has acted consistently or inconsistently with its NAFTA obligations.48 We see no basis in the DSU for panels and the Appellate Body to adjudicate non-WTO disputes. Article 3.2 of the DSU states that the WTO dispute settlement system "serves to preserve the rights and obligations of Members under the covered agreements, and to clarify the existing provisions of those agreements". (emphasis added) Accepting Mexico's interpretation would imply that the WTO dispute settlement system could be used to determine rights and obligations outside the covered agreements. In light of the above, we do not see how the PCIJ's ruling in Factory at Chorzów supports Mexico's position in this case.
For all these reasons, we uphold the Panel's conclusion, in paragraphs 7.1, 7.18, and 9.1 of the Panel Report, that "under the DSU, it ha[d] no discretion to decline to exercise its jurisdiction in the case that ha[d] been brought before it." Having upheld this conclusion, we find it unnecessary to rule in the circumstances of this appeal on the propriety of exercising such discretion.49