On Thursday morning, Mr Santer and his minder, Klaus Kinkel, the German Foreign Minister, looked the assembly full in the face and asked it what it was rebelling against. And the European Parliament stared back between half-closed eyes, shrugged its shoulders, and asked: What have you got?
The rebel without a cause has not yet come of age, but it is well into adolescence, feistily saying no when it can and starting to get its own way, though unsure of what that is. There is everything to look forward to over the parliament's five-year term: it is emerging as a real place of power and influence.
Often over-verbose, given to 'serial junketing', absenteeism, silly national political games that achieve little, and incomprehensible inter-party jousting, it attracts little interest from the outside world or even the other European institutions.
'We ignore 98 per cent of what they do,' said one official of the European Commission recently. 'They are second-rate people doing third-rate work.'
But on Thursday, as the parliament moved to a vote on Mr Santer, a knot of concerned and important faces could be seen on the television monitors that show the assembly floor.
There was Jacques Delors, the outgoing president; David Williamson, the commission's secretary-general; Sir John Kerr, the British Ambassador, who had flown down at the suggestion of his staff, for what looked like an emergency; the Luxembourg ambassador and Mr Santer, with Mr Kinkel.
There was Pauline Green, a former policewoman, now MEP for London North and head of the Socialist Group, delivering a stern rebuke to the Council of Ministers, the most powerful body in the European Union. And Mr Kinkel, a man you would not care to meet in a sunlit plaza, let alone a dark Strasbourg alley, was flinching before her whiplash rhetoric.
Mrs Green later told BBC radio: 'We have given everybody a bit of a scare, because for too long the parliament has been a rubber stamp. They can no longer take that rubber stamp for granted.'
The mechanism that the parliament is using to win influence is threatening to upset choices made by the Council of Ministers, such as that of Mr Santer, or a telecommunications bill killed off on Tuesday. Mrs Green meant to talk about a crisis of confidence on Thursday; but she ended up referring, twice, to a 'confidence of crisis', which sums up the parliament's attitude and the state of affairs in the EU.
In the process, the European assembly is emerging as something closer to the US Congress than the British Parliament. It is a check on the power of the commission and the Council of Ministers, if still an ineffective one.
Over the next year, under the leadership of the new parliament president, Klaus Hansch, it will push its powers to the brink. What it lacks, however, is a sense that it has its own agenda, a programme to achieve.
But an agenda is emerging. First and foremost, the parliament is a lobby for institutional reform, to achieve new powers for itself and the Union. At the moment it can call spirits from the deep, but they do not come, because the sections of the Maastricht treaty that deal with spirit-calling give the assembly few powers. In 1996, when EU leaders gather to rewrite that wretched document, it is likely the parliament will gain influence, perhaps decisively.
The second area where the parliament wants to make its mark is employment. With a centre-right Christian Democrat at the commission and a powerful left-wing bloc in the parliament, there clashes are likely over the prevailing mood that deregulation, rather than new spending, is the way to reduce the dole queues.
Mrs Green and the Socialists have created a committee to sketch out new possibilities for increasing jobs, and will make their own report to the Essen summit in December.
The third area is foreign affairs, where the parliament is starting to blaze a trail. It is a wobbly path at the moment, more or less on the lines of liberal internationalist.
If you think the parliament does not matter, head down to Strasbourg sometime and see the lobbyists handing out chocolate from the Ivory Coast, watch the Taiwanese journalists anxiously scrutinising emergency motions, British diplomats agonising over blocked aid for Syria, the Central Europeans investigating why the parliament has blocked funds for assistance programmes.
One of the biggest running battles is over the funding of the EU's common foreign and security policy, which may yet derail its overseas actions. Not for nothing did newly arrived Labour MEP Glenys Kinnock choose the parliament's Committee for Relations with the Third World as a place to make her mark.
What the parliament still seems to lack is a sense of legitimacy. The election turnouts were very low this year, even in such countries as the Netherlands, whose people have a keen sense of the importance of democracy in Europe.
The attempt to block Mr Santer was derailed by heavy lobbying from governments in Spain, Greece, Portugal and Denmark, showing that the transnational parties are still something of a fiction.
Party discipline is still quixotic. But when the teenage parliament threatened to chuck out Mr Santer - probably no more popular in Stafford or Saarbrucken than Strasbourg - it made a start.