A theory of external judicial politics: the ECJ as cautious gatekeeper in external relations

Figures & data

Figure 1. A model of bounded ECJ discretion in external judicial politics.

Table 1. Summary table.

		Opinion 1/76 (Fund Tribunal)	Opinion 1/91 (EEA Court)	Opinion 1/94 (WTO DSB)	Opinion 2/94 (ECtHR I)	MOX Plant (UNCLOS)	Opinion 1/09 (ECPC)	Opinion 2/13 (ECtHR II)	Achmea (Intra-EU ISDS)	Opinion 1/17 (ICS)	Komstroy (intra-EU ISDS)
European case law identifier		ECLI:EU:C:1977:63	ECLI:EU:C:1991:490	ECLI:EU:C:1994:384	ECLI:EU:C:1996:140	C-459/03	ECLI:EU:C:2011:123	ECLI:EU:C:2014:2454	C-284/16	ECLI:EU:C:2019:341	C-741/19
Time period		1977	1992	1994	1996	2006	2009	2014	2019	2019	2021
Core question put to ECJ		Commission: Is the agreement on the European laying-up Fund compatible with European law?	Commission: Is the proposed EEA Court compatible with European law?	Commission: Is the EU competent to conclude GATS and TRIPS Agreements including provisions on the WTO Dispute Settlement Body?	Council of Ministers: Does the EU hold the necessary competences to accede to the ECHR and ECtHR?	Commission: Is Ireland’s resort to UNCLOS arbitration compatible with European law?	Commission: Is the ECPC compatible with European law?	Commission: Is ECtHR membership compatible with European law?	German Federal Court of Justice: Is intra-EU investment arbitration compatible with European law?	Belgian government: Is the Investment Court System compatible with European law?	Paris Courts of Appeal: Is intra-EU investment arbitration under the Energy Charter Treaty compatible with European law?
Independ. variables	Geographic overlap	0.90 (Eurocentric)	0.90 (Eurocentric)	0.12 (Global)	0.57 (Eurocentric)	0.15 (Global)	0.72 (Eurocentric)	0.57 (Eurocentric)	1.00 (EU-centric)	0.15 (Global)	0.52 (Eurocentric)
	Substantive overlap	Low	High	High	Low	High	High	High	High	High	High
	Regime centrality	Secondary regime	Secondary regime	Core regime	Secondary regime	Secondary regime	Secondary regime	Secondary regime	Secondary regime	Core regime	Secondary regime
Intervening variable	Preference constellation of key actors	Minor interest & divisions:	Minor divisions:	Unanimous support for participation:	Minor divisions:	Minor interest & divisions:	Strong interest & divisions:	Support for participation:	Strong interest & divisions:	Unanimous support for participation:	No formal position on substance:
		Council is mostly concerned about the EU’s external competences; DK and UK voice concerns over the Fund Tribunal’s impact on the European legal order.	BE and UK deem EEA Court compatible with European law; most Member States, Commission, Council of Ministers and Parliament remain silent on compatibility; only ES deems EEA Court incompatible.	Council of Ministers and Commission consider GATS, TRIPS and thus DSU compatible with European law; disagreements only over exclusive or mixed ratification.	AU, BE, FI, DE. IT, GR, SE support accession; FR, PT, ES, IE, UK question need and EU competence to accede.	IE and SE deem UNCLOS arbitration compatible; Commission deems it incompatible; no further submissions	CZ, DK, DE, EE, NL, PL, PT, RO, SI, FI, SE and UK consider ECPC compatible with European law; BE, FR, Parliament and Commission suggest minor amendments; IE, GE, ES, IT, CY, LI and LU consider ECPC incompatible with European law.	Council of Ministers, Commission and Parliament deem ECtHR membership generally compatible with European law; some however acknowledge the potential for legal-judicial tensions.	AU, DE, FR, NL, FI deem intra-EU investment arbitration compatible; CZ, EE, GE, ES, IT, CY, LV, HU, PL, RO, SK and Commission deem it incompatible.	Council of Ministers and Commission deem ICS compatible with European law; BE voices some concerns mostly to clarify legal situation.	Council of Ministers, FR, FL, HU, SE deem ECJ not competent to render preliminary decision in that core dispute only concerns non-EU parties.
Dependent variable	ECJ ruling	Non-cooperative	Non-cooperative	Cooperative	Non-cooperative	Non-cooperative	Non-cooperative	Non-cooperative	Non-cooperative	Cooperative	Non-cooperative
Theoretical evaluation of findings		Support for H1.2	Support for H1.2	Support for H1.1	Support for H1.2	Support for H1.2	Support for H1.2	Support for H1.2	Support for H1.2	Support for H1.1	Support for H1.2

Evaluating the importance of regime overlap and centrality: Hypotheses H_1.1 and H_1.2 stipulate that jurisdictional overlap between the European legal order and the relevant international tribunal and regime as well as regime centrality affect ECJ jurisprudence. Do tribunal and regime properties and ECJ rulings co-vary as expected? And to what extent do different properties qualify as sufficient or necessary conditions for cooperative or non-cooperative ECJ rulings in the given set of ECJ cases?.

Figure 2. Ideal-type representation of internal and external judicial politics.

Table 2. Crisp-set truth table.

Geographic overlap	Substantive overlap	Regime centrality	Outcome	Count	Case name
1	1	0	0	5	Opinion 1/91; Opinion 1/09; Opinion 2/13; Achmea; Komstroy
1	0	0	0	2	Opinion 1/76; Opinion 2/94;
0	1	0	0	1	Mox Plant
1	1	1	0	0
0	0	0	0	0
0	0	1	0	0
1	0	1	0	0
0	1	1	0	0
0	0	1	1	0
0	1	1	1	2	Opinion 1/94; Opinion 1/17
1	1	1	1	0
0	0	0	1	0
1	0	0	1	0
0	1	0	1	0
0	0	1	1	0
1	1	0	1	0

Note: Geographical overlap is coded as 1, if labelled Eurocentric and 0 if labelled global in Table 1; substantive overlap is coded as 1, if reported as high and 0 if reported as low in Table 1; regime centrality is coded as 1, if it is reported as a core regime and 0 if it is reported as a secondary regime in Table 1; outcome is reported as 1 if ECJ decision is cooperative and 0 if it is non-cooperative.