Why Liz Truss Will Be the U.K.’s Next Prime Minister

Her success has two causes. First, winning over the membership requires not offering policy proposals but creating a mood. Mr. Sunak, as befits a former chancellor, has created a mood of sober realism. At the Exchequer he failed to deliver the lower taxes that Conservatives seek. Being chancellor and having to make tough decisions is seldom a springboard to becoming party leader.

Ms. Truss, by contrast, has created a mood of optimism. The British, she insists, are well able to master whatever is thrown at them and come out on top.

Boris Johnson

created a similar mood, both in the Brexit referendum of 2016 and as prime minister during Covid—one reason many Conservatives are sorry to see him go. So did

Ronald Reagan

in America. Before Reagan trounced

Walter Mondale

in 1984, New York Gov.

Mario Cuomo,

a Democrat, said his mother-in-law had begged him to tell Mondale to stop saying how awful everything was. “We already know!” she said.

The second reason for Ms. Truss’s success is Europe, which divided the Conservative Party for nearly 60 years. Today, however, almost all Conservatives want to keep the U.K. at a distance from the Continent. The more euroskeptic candidate therefore can be expected to win.

Unexpectedly, euroskepticism is helping Ms. Truss, not Mr. Sunak, even though he was a Brexiteer during the referendum, shunning warnings that it would harm his career, while she was a Remainer.

Ms. Truss, however, is now the repository of Brexiteer hopes. Most Brexit supporters believe the deal will swiftly yield dividends. The goal is to free the economy and push for growth, enlisting neoliberal policies such as slashing regulations, taxes and subsidies. Those policies were successful in the long run in Australia and New Zealand over the 1970s. But in the short run they were costly, particularly to farmers deprived of subsidies. The danger, as Reagan found out, is that tax-cut enthusiasts don’t necessarily favor the cuts in public services needed to finance them. Many economists are skeptical of Ms. Truss’s economic plan, though a minority support her.

All told, the campaign has been depressing. Neither candidate has admitted that, whether or not taxes ease, living standards will fall because of higher food and energy prices owing to Covid and the Ukraine war. The candidates haven’t pinpointed how they would control rising inflation. Nor have they said what they would do to rescue Britain’s crumbling National Health Service, now just behind the economy in voter priorities.

These deficiencies might be due to the wide gulf on policy priorities between Conservative members of Parliament and party members on the one hand, and the voting public on the other. Research has shown that only 5% of Conservative parliamentarians and 22% of Conservative members agree that there is one law for the rich and one for the poor, a view held by 72% of the voters. Among voters who switched to the Conservatives in the 2019 general election, 81% believe that big business takes advantage of ordinary people, a view held by only 18% of Conservative members of Parliament and 34% of party members. Conservative membership figures have declined from more than a million in the mid-1970s to about 160,000 today. This dwindling membership, moreover, is unrepresentative of the voters whom the Conservative Party needs to attract if it is to remain in government, being 97% white, 71% male and 57 years old on average.

During the leadership contest, the candidates have been speaking to the party. The new prime minister will have to speak to the people.

Mr. Bogdanor is a professor of government at King’s College, London and author of “Britain and Europe in a Troubled World.”