Can a coalition of strongly conservative, older and working-class voters fed up with what they regard as a too-powerful and distant institutions fall in line with a charismatic big-city politician whose hair is a running joke, and change their country’s direction?

One of the world’s most important democracies is about to find out.

And no, we’re not talking about the United States.

Over the weekend, British Prime Minister David Cameron finished negotiations on a package of reforms that he says will give his country more flexibility in its relations with the European Union. The stage is now set for a referendum on whether Britain stays in the EU, which Cameron promised back in 2013, mostly to assuage a contingent within his own Conservative Party that wants out. The vote will be held June 23. Opinion polls indicate that it is likely to be close.

No country has ever voted to leave, and the controversy comes at an awkward time for the 28-member EU. It is struggling with an immigration crisis, economic woes, and a nagging feeling among many, reflected in populist right-wing movements in several countries, that the drive for an “ever-closer union” has gone far enough – if not too far. 

That in itself appears to be one expression of a broader phenomenon affecting much of the Western world, including the U.S. It is reflected in deep disenchantment with politicians, government and other large institutions; a concern with securing borders; and a stronger focus on the national interest.

The concessions Cameron won seem modest enough. The most concrete appear to be those that give Britain the right to limit public-assistance payments to migrant workers from poorer EU countries who traveled to the United Kingdom to find a job. Britain has been a member since 1973, but never joined the euro zone, preferring to keep its own currency.

Cameron says what he wrangled from EU officials is sufficient, and that he will campaign to remain in the union.

However, six of his own Cabinet ministers support leaving the EU.

The anger doesn’t seem as raw in Britain as it does among some U.S. primary voters. But four months ahead of the referendum, the country seems closely divided. One widely cited poll in recent days put the anti-EU, or so-called Brexit, vote slightly ahead – with about a quarter of those who say they’ll vote undecided.

Surveys conducted over time by YouGov indicate a very tight race, and also show where the battle lines are drawn:

 • Younger people strongly favor staying in the EU. The majority of those over 50 favor leaving.

• 64 percent of those who describe themselves as fairly or very left-wing favor remaining. An identical percentage of those who are fairly or very right-wing want out.

• Those who vote for the Conservatives favor a Brexit by a 55-45 margin. More than 60 percent of Labor, Green, Liberal Democrat and Scottish National Party voters favor remaining in the EU. 

As Peter Kellner wrote in an analysis accompanying the YouGov poll results, one key will be whether working class voters who tend to favor leaving the EU, actually turn out to vote.

In this piece, the Financial Times finds growing support for the strongly anti-EU UK Independence Party in an unlikely place – Wales, which is a major beneficiary of EU policies. The party has built support on concerns over immigration and the frustrations of former blue-collar workers over lack of jobs. The result is that Wales as a whole may well vote to leave the EU.

Now, about the hair.

The one element the Brexit crowd was missing was a major political figure to focus the campaign. That changed Sunday when London Mayor Boris Johnson announced his support for leaving the EU.

Kellner wrote back in January that Johnson’s position was likely to be an important factor. He is one of the country’s most charismatic politicians (and his hair is wild enough that it has its own Twitter feed). Cameron had hoped he could persuade Johnson, a fellow Conservative who is thought to have ambitions to become prime minister one day, to join the pro-EU campaign.

Johnson said Sunday that Cameron had done a good job negotiating with EU officials, but that the result fell short of fundamental reform. The EU limited British sovereignty, he said.

The campaign will take place at a time when the EU’s struggles make it harder to argue for staying the in the union. On the other hand, just as with the referendum on Scottish independence a year and a half ago, voters may decide they’re not ready for such a drastic step. Among other things, there is no surer way to trigger a second vote in Scotland for independence.

Game on.