LONDON — David Cameron promised to end his party’s obsession with Europe. Instead his premiership will be defined by it.

The British prime minister is all but certain to suffer his own ignominious departure if Britain votes to exit the European Union. To Cameron’s critics it would be a fitting end to a political career laced with opportunistic Brussels bashing — the ultimate comeuppance for years of pandering to Tory prejudice.

“You can’t spend years and years and years trashing the European Union in order to curry favor and expect people to all along understand that you didn’t really mean it,” one senior member of the previous Tory-led coalition government told POLITICO.

Those who have worked with Cameron reject any notion of a “Damascene conversion” on Europe. Despite his instinctive Euroskepticism and passionate opposition to the euro, he has never supported withdrawal.

“What people always forget is how preoccupied he is with being seen as a successful leader of his party” — a former cabinet minister

For those who know him well, his decision to risk the wrath of his party to campaign wholeheartedly for Remain is the combination of cold self-interest in winning and deeply held conservatism which favors the concrete benefits of the status quo. Above all, his drive to stay in the EU is the result of a ferocious determination to restore Tory dominance in Westminster.

“He’s absolutely fixated on going down in history as the Conservative Party leader who returned the Conservative Party back to good sense and power,” said the senior minister in the previous coalition government, speaking on condition of anonymity.

A party split caused by Brexit is the major threat to Conservative Party hegemony that he hopes to make his legacy.

Tory pragmatist

Unlike Tony Blair, Cameron did not choose his party — he was born into it. “The one bit of his conviction you can never underestimate is the unbelievably strongly held view that chaps like him should be in charge,” the former cabinet minister said.

“What people always forget is how preoccupied he is with being seen as a successful leader of his party,” said the source. “He remains a Conservative Party leader first and a good prime minister second.”

Cameron does not want his premiership defined by Europe, but by late 2012 he calculated that a referendum was unavoidable and the Tories needed to finally put the issue to bed to get back to the task of crushing Labour in 2020.

Once the decision was made the only pragmatic option was to back Remain — primarily because the risks of leaving are too great and he calculated the country would never vote for it.

Long-term Cameron ally Michael Gove, the justice secretary who is campaigning for Brexit, has described him as “the kind of poker player who waits and reads the other players and bets when he knows the alignment is in his favor.”

It is the kind of description which crops up again and again. One veteran Conservative MP who knows the prime minister well said: “He’s a pragmatist — his prejudices are Euroskeptic, but he has to think about what is best for the government and the party for being reelected.”

The Tory MP said Cameron had simply taken the view that Remain would win. “It’s not that he believes it. He comes to a view on what is best and then starts to believe what he is saying. He used to share my prejudice for liberalizing drugs but he dropped that on becoming PM.”

Euroskeptic roots

In October 2011, Cameron and the then Foreign Secretary William Hague led the charge against holding an In/Out referendum, arguing that it was not in Britain’s interest and would weaken its bargaining power.

Just 15 months later, in January 2013, he had performed a complete volte face.

Cameron certainly started out as a Euroskeptic.

Former Downing Street foreign policy adviser Sir Stephen Wall, who got to know Cameron in the early 1990s when they briefed John Major, told POLITICO that at the time the future prime minister was “one of those for whom loyalty to the former leader [Margaret Thatcher] was synonymous with being anti-European.”

Wall added: “There is a story [former Labour MP and ex-Europe Minister] Denis MacShane tells where he bumped into Cameron in the locker room in the House of Commons gym. Denis offers to give some advice on how to ‘handle’ Europe, but Cameron says: ‘Denis, you don’t seem to realize that I am a skeptic. That is my view.’”

Cameron, whose father read the fiercely anti-EU tabloid the Daily Express, joined the Conservative Party as a researcher at the height of Thatcher’s power and certainly showed no early sign of demurring from her antagonism to Brussels.

His Euroskeptic credentials were further honed as the special adviser to former Chancellor Norman Lamont — now an enthusiastic Brexit supporter — in the 1990s.

As an MP, Cameron said his “passionate” opposition to the euro was formed during the “humiliating experience” of watching Britain being kicked out of the exchange rate mechanism, the forerunner to the euro, under Lamont’s stewardship.

Later, as a backbench MP Cameron described himself as a “genuine skeptic” and railed against the “monstrous” EU directive from Brussels introducing the European arrest warrant — which he now supports.

As party leader, Cameron pulled Conservative MEPs out of the European Parliament’s center-right European People’s Party because, he claimed, it was too federalist.

Yet, despite all of this, and much to his frustration, Cameron’s Euroskepticism has often been questioned.

Despite his pragmatism, those who know him insist Cameron’s stance has shifted subtly — but nevertheless genuinely — in favor of the EU during his time as prime minister.

When applying to be the Conservative candidate for Witney, the safe seat in Oxfordshire which he won in 2001, he was originally put down as a question mark on an internal party list of Euroskeptics.

Cameron challenged the ruling — eventually getting it overturned — declaring: “These are my views: no to the single currency, no to further transfer of powers from Westminster to Brussels and yes to renegotiation of areas like fish where the EU has been a disaster for the U.K. If that is being a Europhile, then I’m a banana.”

However, Cameron also admitted then that he was not an outer: “The answer is no.”

Learning to love Europe

Despite his pragmatism, those who know him insist Cameron’s stance has shifted subtly — but nevertheless genuinely — in favor of the EU during his time as prime minister.

“I certainty noticed when I was sat around the cabinet table that at the beginning he had quite cardboard cut-out, cheap gags about how ghastly the European Union was and how tedious the European summits were,” the former senior coalition minister said.

The PM began to drop this act after two diplomatic setbacks in his first term.

“He was very put out by the time when [German Chancellor Angela] Merkel and [French President François] Hollande went to Ukraine for a summit with Putin on their own and didn’t inform him. I think that was quite important,” the source said.

"What he discovered in that process is when he puts his mind to it he’s a bloody good negotiator on behalf of the U.K. in these summits” — former coalition figure

The prime minister was also bruised by the 2011 debacle when he opposed a proposed fiscal compact but was ignored anyway, figures close to the negotiation said.

Number 10 rejects this portrayal of events but admits Cameron’s position has hardened in favor of EU membership as a result of his sobering experience as a PM who has found the hard way that he needs to work with Brussels.

A senior Downing Street source said: “He would say sanctions against Russia from the whole of the EU only exist because of the U.K. This is something we wanted to do as a country but our force was magnified and amplified by being part of the EU.”

The prime minister privately points to the migration crisis as a moment that helped shape his thoughts in Europe.

The Downing Street source said: “On migration we had an opt out so we were not in a situation where we have to take people. But he went to the European Council and had a seat at the table.

“He was there at 2:30 a.m. helping them come up with a deal to make sure that migration was properly handled and dealt with because that was a massive influence on the U.K.,” said the source. “He thought that that was a particularly strong example of how you can actually make a difference by just being there.”

After the early bruising encounters in Europe, Cameron’s coalition colleagues felt that he had learned to play the Brussels game and even developed a “slight proprietorial affection” for the EU leaders’ club.

The former coalition figure said: “He’s an incredibly quick learner, a very versatile politician. If he bumps up against an obstacle he will think hard about how to maneuver himself around it more successfully next time and that’s what he did. What he discovered in that process is when he puts his mind to it he’s a bloody good negotiator on behalf of the U.K. in these summits.”

Cameron has also been left in no doubt about Washington’s view. “I was told by very, very, very senior members of the U.S. administration they just simply don’t get at all why on earth he is even risking Britain leaving the European Union,” said the source.

The answer, for Cameron, is that he had no choice. It was the pragmatic decision to make.

Demolishing Labour

A series of columns for the left-wing Guardian newspaper between 2001 and 2005 when Cameron was an aspiring MP and backbencher give the clearest outline of his broader political philosophy, most notably an instinctive conservatism and a determination to win.

In January 2005, less than a year before becoming Tory leader, Cameron wrote that the principle of his thinking was that “concrete benefits of an existing society must be taken more seriously than potential, abstract benefits” of some other system.

This is the Cameron plan: Get the referendum out of the way and then concentrate on burying Labour.

The burden of proof, he said, should “always lie on those proposing change.” This now forms the centerpiece of his campaign against Brexit whenever he is asked what would happen if the U.K. did pull out of the EU.

If Tories are to win elections, Cameron wrote, they need “a relentless focus on the things that people care about in their daily lives.” And to Cameron, crucially, Europe is not one of these things.

His underlying reading of British politics has remained remarkably constant. He still believes the Tories need to fight the 2020 election on issues that really preoccupy the public and is planning a blitz of announcements designed to plant the party firmly in the center ground after the referendum.

This is the Cameron plan: Get the referendum out of the way and then concentrate on burying Labour.

To some, this relentless focus on winning marks him out as untrustworthy.

The only time Cameron has shown real conviction on an issue other than the euro is on the hunting ban, which he admitted getting “really angry” about and “losing it” with Labour MPs.

But even on this he has yet to reverse the legislation in the Commons, or even try to, because the majority of MPs favor the ban.

Last roll of the dice

Although he has pledged to carry on as prime minister in the event of a vote to leave, many Conservative MPs privately insist Cameron cannot credibly hope to negotiate a new deal with the EU.

Cameron’s former mentor Michael Howard, a former Tory leader, said Tuesday that Cameron could stay on in Number 10 but would have to nominate an outer to lead the talks if he lost the June 23 poll in a bid to unify the party.

By contrast, if Cameron can secure a comfortable win, he is expected to quickly carry out a “unity reshuffle” of his cabinet.

Such an arrangement would leave him prime minister in name only, staying in position to calm the markets before the Tories elected a new leader once the initial turmoil had calmed.

One Conservative minister, a passionate supporter of EU membership, said Cameron would struggle to stay on after a vote to leave: “It would be tough. When you’re identified to such an extent with one side, to turn around and say ‘forget all that stuff.’”

By contrast, if Cameron can secure a comfortable win, he is expected to quickly carry out a “unity reshuffle” of his cabinet, with top jobs for Brexit supporters deemed to have behaved reasonably in the campaign.

The prime minister’s journey from ambitious Euroskeptic to passionate EU defender is far shorter than at first sight.

He has never wanted Britain to leave the EU and would rather not be having the discussion.

But now that he is, he knows what he needs to do — for his own sake and in his view, that of his party.