Maastricht came into force on November 1, 1993, committing member states to an ambitious programme of closer political and economic cooperation, all coordinated in Brussels and ultimately leading to the single currency, launched in 1999.
This "great leap forward" to monetary union was on a different scale from anything before and since but analysts say it was incomplete, without the necessary elements to ensure that the rules were followed by all.
Maastricht notably set limits for national budget deficits -- the shortfall between government spending and revenue -- at three percent of Gross Domestic Product, and at 60 percent for total debt.
But dangerously, the rules were only half-heartedly enforced, with the top two of France and Germany breaching the limits with apparent impunity.
By the time the global financial crisis broke in late 2007, many member states had chalked up huge debts and a few years later as bailout costs soared, no less than 25 of the 27 then EU states had fallen foul of the Maastricht rules.
EU leaders are now trying to repair the damage, with the 17 -- soon to be 18 -- eurozone countries aiming to put in place a framework with penalties and rewards to ensure the rules are really kept this time.
Looking back to the Maastricht negotiations, analyst Daniel Gros of the Center for European Political Studies says "the will just wasn't there" for governments to make the hard choices needed.
Comparing that generation of leaders to generals who plan for past wars instead of the threats ahead, Gros said the Maastricht set were more concerned with fighting inflation and did not anticipate systemic problems with the banks.
The Maastricht Treaty did not prepare Europe for "the major challenges to financial stability" at the heart of the crisis, he said.
Nicolas Veron of the Bruegel Institute think-tank said even at the time, many observers had warned it was "madness" to plan a single currency without the full economic, political and banking union required to make it work.
Absence this essential support for any currency, when the banks collapsed, they threatened to bring down the whole system, driving the eurozone into a deep recession and forcing governments to adopt harsh austerity programmes.
In response, EU leaders tried to combat the crisis on the run, improvising reforms to put Europe back on track, said Jean-Dominique Giuliani of the Schuman Foundation.
Despite the failings, however, Giuliani feels that Maastricht was still "the last time the EU set itself a major objective".
"Since then, there has been nothing," he said.
---- Growth of anti-EU sentiment ----
It is not that the EU has stood still.
It has welcomed many of the former Communist states of the Soviet bloc as members in recent years and seeks a global role and voice but that is not enough to bolster faith in the project.
The crisis has come at more than just an economic cost -- the painful austerity measures taken to tame it have alienated many supporters of the European project.
The fallout has stoked a backlash against Brussels in many member states who are increasingly reluctant to see national powers handed over in the name of policy coordination.
Indeed some such as Britain talk of winning power back while anti-EU sentiment is on the rise even in stalwarts such as France ahead of European Parliament polls in 2014.
Today's leaders are wary of action given "the fears of governments and EU institutions that euro-critical forces might win even more support", said European Policy Centre analyst Janis Emmanouilidis.
He listed parties on the rise in at least nine EU states and today sees no "transnational message about why the EU matters, backed up by concrete policy proposals that go well beyond the lowest common denominator".
Former French president and a key figure in the creation of the euro, Valery Giscard d'Estaing also says there is no longer any "Big Idea" driving the EU.
His suggestion -- "build Europe up as an economic power" on a par with United States and China -- is backed by Giuliani of the Schuman Foundation.
The sort of EU-wide tax and welfare reforms plus the centralised authority to make it all work seem a distant prospect, with the process needing the legitimacy conferred only by comprehensive democratic support.
For former European Central Bank head Jean-Claude Trichet that means integration requires "reinforcing" the European Parliament's still-limited powers.
Greater democratic accountability could of course at the same time leave the EU hostage to euro-critical forces -- and would also, of course, require another treaty to come about.