First, it is of course much easier to say things like
These objectives shall be pursued by appropriate means, depending on the extent to which the relevant competences are attributed to the Union by this Constitution [§3.5]than to write out what bodies of government have what powers to achieve this result. Why one can even write self contradictory things like
balanced economic growth and social justice, with a free single market [§3.2]and not sweat the details. In my field we call this marketecture, not something you could actually use to build a working system but some dreamers' vision of "good stuff".
The second is something I've touched on before which is "logo-realism". This is the belief that words are primary and that physical reality can be shaped by using the right words. We see this a lot on the Left these days, where many peaceniks believe that talking about liberating the Iraqi people is better than actually fighting for it. The EU Constitution seems to be a severe victim of this, with declarations like
Fundamental rights, as guaranteed by the European Convention for the Protection of Human Rights and Fundamental Freedoms, and as they result from the constitutional traditions common to the Member States, shall constitute general principles of the Union's law.where saying that the EU will preserve existing rights among multiple nations which may conflict with each other or other sections of the EU Constitution is apparently sufficient to deal with these issues. (this is classic marketeture - "oh yeah, of course it will work on Windows, Solaris, Linux and MacOS Xsimultaneously in a distributive fashion!"). The words are there, the right people read them and approved of them - how could it not work?