Once the Council has found that it is necessary to improve the existing level of protection as regards the health and safety of workers and to harmonise the conditions in this area while maintaining the improvements made, achievement of that objective through the imposition of minimum requirements necessarily presupposes [Union]-wide action, which otherwise, as in this case, leaves the enactment of the detailed implementing provisions required largely to the Member States. The argument that the Council could not properly adopt measures as general and mandatory as those forming the subject-matter of the directive will be examined below in the context of the plea alleging infringement of the principle of proportionality.166
The quoted passage contained two fundamental choices. First, the Court assumed that where the Union had decided to ‘harmonise’ national laws, that objective necessarily presupposed Union legislation. This view answers the national insufficiency test with a mistaken tautology: only the Union can harmonise laws, and therefore the Member States already fail the first test!
But assuming the ‘whether’ of European action had been positively established, could the Union law go ‘as far’ as it had? This was the second crucial choice of the Court. It decided against the idea of subsidiarity in a wider sense. For, instead of analysing the intensity of the European intervention under Article 5(3) TEU, it chose to review it via the principle of proportionality under Article 5(4) TEU. And it is there that the Court made a third important choice. In analysing the proportionality of the Union law, it ruled that ‘the Council must be allowed a wide discretion in an area which, as here, involves the legislature in making social policy choices and requires it to carry out complex assessments’. Judicial review would therefore be limited to examining whether the legislature’s discretion ‘has been vitiated by manifest error or misuse of powers, or whether the institution concerned has manifestly exceeded the limits of its discretion’.167 The Court would thus again apply a low degree of judicial scrutiny.168
Choices one and three have been confirmed in subsequent jurisprudence. By concentrating on the national insufficiency test, the Court has short-circuited the comparative efficiency test.169 It has not searched for qualitative or quantitative benefits of European laws, but confirmed its manifest error test – thus leaving subsidiarity to the political safeguards of federalism.
Quoted passage springs from para 47. It's obvious why I'm addled? The first red sentence (in screenshot) says "two fundamental choices", but the brown underlines show three choices.