The parallel between the unrest of Conservative backbenchers over Maastricht and the determined Euro-scepticism of the 2010 intake of Tory MPs was obvious at the time of the Commons vote earlier in the year.
But signs of 1990s-style disorder spreading to the centre are far more perilous for the Government's standing. More importantly, it could be disastrous for the country.
For the moment, Cameron can console himself that he goes into the euro turmoil far stronger than the hapless John Major, who was haunted by Alastair Campbell's cruel observation of his sartorial gaffe.
Yet, the stakes for the British economy are now so high that a Major-like failure to act decisively could destroy Cameron's carefully crafted image of an assertive leader.
The problems facing the euro and the economies of all 27 EU member states are severe and unprecedented. Britain will be profoundly affected by any hastily agreed change in the rules governing the eurozone, but risks being shut out of negotiations as a non-euro member. The danger for the UK is the sign that Cameron's own internal difficulties are making him too weak to play this tough hand effectively.
At times, his laissez-faire attitude to dissent within the coalition has been astute, allowing opposing sides to let off steam without rocking the boat. But at this critical moment, allowing ministers as senior as Nick Clegg and Iain Duncan Smith to contradict each other publicly is profoundly destabilising. Most serious is Cameron's inability to shed the millstone of the anti-European dogma that helped propel him to the top of the Tory party.
At a time when Britain needs a prime minister who will win in Europe for the national interest, we have a leader on the sidelines who spends more time negotiating with his own party about repatriation of powers than his European allies.
John Woodcock is Labour MP for Barrow and Furness, and a former spokesman for ex-prime minister Gordon Brown.