The U.K. Elections Are a Political Wake-Up Call

Sometimes local elections tell a bigger story, and so it is with a trio of parliamentary by-elections in the United Kingdom this week. The governing Conservative Party was fighting to retain three seats after the incumbents, including former Prime Minister Boris Johnson, resigned. The Tories lost two of them, while hanging on by their fingernails in the third.

The worst defeat was in a North Yorkshire district held by the Tories since 2010. In the last election four years ago, their candidate won by around 20,000 votes. This week the opposition Labour Party flipped the seat with a margin of around 4,000 votes. A similar reversal happened in the west of England, where a seat the Tories had held since 2015 and won by around 19,000 votes last time switched to the centrist Liberal Democrats, with a margin of 11,000 votes.

The economy loomed over the election like a rain cloud, as opinion polls point to greater economic pessimism than at any time since 2008. One message is that Prime Minister Rishi Sunak’s program—painful tax increases to try to stabilize the government budget, with no other plan for economic growth—is a loser. Any Tory advantage on other issues, such as illegal immigration, won’t save them in the national election expected next year.

Nor can the Tories expect Labour to make many mistakes this time around. Mr. Johnson won a historic victory in 2019 running against former Labour leader Jeremy Corbyn, whose far-left economic and cultural views offended even many longtime Labour voters. Keir Starmer, Mr. Corbyn’s successor, has made Labour a safe alternative again by dialing back the party’s big-spending, big-taxing ambitions.

The one caveat is environmental policy, which narrowly cost Labour the third seat up for grabs this week. The Tories held Mr. Johnson’s old district in suburban London by fewer than 500 votes, compared with a margin above 7,000 in 2019. Even the victorious Tory candidate concedes that he would have lost except for protest votes cast against Labour to oppose the plan by London’s mayor to expand a green levy on older cars driving in the city.

The twin warnings are that parties of the right need to offer voters a plausible economic-growth message, while parties of the left need to moderate their extreme green agendas. Coming elections, in Britain and beyond, will turn on which side learns which lesson the fastest.