He has also raised the possibility of imposing curbs on immigration.
The talk may play well with the conservative British press, but it has fizzled across the Channel.
Cameron initially gained nods of agreement from other leaders when he said the EU had become over-bearing, bureaucratic and wasteful in the eyes of many Europeans.
Today, though, he finds himself facing indifference or irritation.
And if he pushes his agenda too far, he will get short shrift at a summit in Brussels on December 18, says Camino Mortera-Martinez of the Centre for European Reform, a London-based thinktank.
Cameron's dilemma is that reducing immigration from other EU countries would mean redrawing the right to work freely across the zone.
Germany - the EU's de facto leader - has slapped this down. Free movement was a founding EU treaty principle and could not be tampered with, Chancellor Angela Merkel said.
But she left open the possibility of discussions on restricting access to benefits, which could be allowed under existing EU law.
"The proposals that were presented now need to be discussed in detail," Merkel said this week.
"Hostility to EU migration has become the most salient issue in British politics, despite evidence of its positive economic impact," said Mortera-Martinez.
"But ultimately, Britain has to face up to reality - the only way to stop European Union migrants entering the country is to leave the EU, with all the economic and geopolitical damage that entails."
Cameron's room for manoeuvre in Brussels has further shrunk because of the changing of the guard at the European Commission, the EU's powerful executive.
The former Commission chief, Jose Manuel Barroso, gently handled Cameron's demands for change, saying it was important for Europe to keep Britain in its ranks.
But there is no love lost between Cameron and Barroso's successor, the blunt-speaking former Luxembourg Prime Minister Jean-Claude Juncker.
Cameron tried to block Juncker from getting the job, saying he was too federalist at a time when Europeans were clamouring for less Europe, not more.
By campaigning loudly in public rather than discreetly behind closed doors, Cameron misread the mood of his European counterparts and came across as a grandstander, pitching boastfully to a domestic audience.
He suffered a humiliating defeat at the summit table - a defeat that Ukip exploited as proof that Europe was deaf to national concerns.
Cameron's image in Europe took a further blow in October when he claimed he had been ambushed by a demand for Britain to pay 2 billion ($3.18 billion) more towards the EU budget.
But there was no ambush. Britain had agreed to the rules, which are based on a country's economic performance, and Cameron's own Finance Minister had been tipped off that a higher payment was on the cards.
With only six months to the elections, Cameron may be tempted to put his get-tough-on-Europe strategy quietly on hold.
This would please his Liberal Democrat coalition partners, who are pro-EU and last month thwarted a Conservative bid to fast-track the referendum.
Reducing the anti-EU rhetoric would also delight British corporations, which are traditionally pro-conservative but say the national economy, and their profits, cannot survive without access to the 28-nation bloc.
Even Margaret Thatcher, an icon for Cameron's generation, fought for the single European market.
The Confederation of British Industry's deputy chief, Katja Hall, said last week: "The UK's openness to trade, people and investment has been the foundation of Britain's success in the past and will remain central in the future.
"Immigration has helped keep the wheels of this recovery turning by plugging skills shortages and allowing UK firms to grow.
"Businesses agree that we must ensure the system rewards those here to work, not the few who do not contribute. But the EU matters to the future of British jobs and growth, so we must work with allies to secure reform."
Yet Cameron could also be tempted to escalate, believing that he has to come up with some sort of victory to win over wavering Conservative voters.
"David Cameron is faced with relentless little-Englander pressure," Michael Leigh, a former EU advisor and now senior fellow at the German Marshall Fund, told the Herald.
"He has chosen not to push back against this pressure, for example by telling the British people more about the numerous benefits they derive from the EU, but to give in to it."
After making a breakthrough in elections to the European Parliament this year, Ukip took two seats from the Conservatives in by-elections in southern England. Opinion polls give it about 14 per cent of voting intentions nationwide.
Under Britain's first-past-the-post electoral system, it is unlikely to get more than a couple of dozen seats in the House of Commons. But by splitting the right-wing vote in middle-class English constituencies that are Conservative strongholds, it would hand Labour a landslide victory.
Cameron must now decide which way to go.
"The European Commission is saying it will accept a calm discussion ... but I do not think it will be up for any dramatic changes of rules or any slap on the table saying 'if [the EU] doesn't accept our changes we will leave the European Union', which is what David Cameron seemed to imply," said Mortera-Martinez.
For Leigh, Cameron's "appeasement" of Ukip sentiment will not work.
"It merely whets the appetite of those who want Britain to leave the EU. It also alienates the friends in Europe, like German Chancellor Merkel, who Mr Cameron needs to deliver a reform package that might assuage British euro-sceptics.
"There is now a 50 per cent chance that Mr Cameron's unsuccessful tactics will produce the result he wants to avoid: British exit from the EU."
