Does he accept the will of the British people and take Britain out of Europe against all his instincts, or will he disregard the democratic mandate put before him, and save his country?
You would be forgiven for assuming the result - whether Remain or Leave - would be legally binding. But it isn't. In some form or another, the government will have to take the final decision as there is nothing in the legislation which says the result must be respected.
David Allen Green has written a good explainer on these legal complexities for the Financial Times. He writes:
What happens next in the event of a vote to leave is therefore a matter of politics not law. It will come down to what is politically expedient and practicable. The UK government could seek to ignore such a vote; to explain it away and characterise it in terms that it has no credibility or binding effect (low turnout may be such an excuse). Or they could say it is now a matter for parliament, and then endeavour to win the parliamentary vote. Or ministers could try to re-negotiate another deal and put that to another referendum. There is, after all, a tradition of EU member states repeating referendums on EU-related matters until voters eventually vote the “right” way.In summary, the result of the referendum is not obligatory. What matters is whether - and when - the government invokes Article 50 of the Lisbon Treaty. This referendum is more of a glorified opinion poll than an out-and-out instruction.
Which brings us back to David Cameron's dilemma: accept the will of the British people and plunge this country, as he sees it, into economic, social and political chaos, or risk his own reputation and legacy to save it.
the migrant camps based in Calais will move to Kent, the NHS will be starved of funding, households up and down the country will lose £4300 per year, Europe could be plunged into another World War, Islamic State will receive a morale boost, house prices will face an 18% hit, Britain will face a year-long recession with 500,000 job losses, pensioners could lose up to £32,000, mortgages will rise by nearly £1000 per year, Britain will face a sterling crisis, the Northern Ireland peace process will be thrown into doubt, the pensions 'triple lock' will be scrapped, and the government will be forced to introduce an 'emergency budget' calling for a combination of tax increases and massive spending cuts.
This is not a prospect that should excite any sitting prime minister. In respecting the will of the people, David Cameron will be consciously choosing to enact all of the above. He will have no choice but to refuse the result as to do otherwise would be completely reckless; potentially the single most irresponsible decision made by a prime minister in British history.
That is, of course, assuming he isn't a liar.