They range from loose cooperation among Member States to the creation of a federal state; from high levels of discretion to strictly binding rules; and from legitimacy that mainly stems from national elections to legitimacy at the European level that is strong enough to speak of a political union.
I am aware that across this wide range some ideas are politically less feasible than others. And it is up to those democratically legitimised to do so to decide how to adjust the Union’s governance structure to best meet the objectives of the EU as enshrined in our treaties.