MADRID (The New York Times) — Spaniards struggling with high unemployment and a credit squeeze delivered a punishing verdict on almost eight years of Socialist government at the ballot box on Sunday, turning to the conservative Popular Party in the hopes of alleviating the pain of Europe’s debt crisis. 

With 99.8 percent of the vote counted Sunday night, the Popular Party, led by Mariano Rajoy, had won 186 seats and a governing majority in the 350-seat lower house of Parliament, while the governing Socialists plummeted to 110 seats from 169. It was the Popular Party’s best showing, and the Socialists’ worst, since Spain’s return to democracy in the 1970s. 

Spain is the third southern European country in two weeks to see its government felled by the debt crisis in the euro zone. In Italy and Greece, prime ministers were forced by mounting financial and economic woes to resign and give way to interim “unity” governments of technical experts, who are meant to take urgent but unpopular austerity measures to cope with the crisis and then call new elections. 

The new Spanish prime minister will have an advantage they lack — the solid backing of a freshly elected single-party majority in Parliament — but he must still cope with the same dire combination of economic stagnation, gaping budget deficits and crushing debts that brought down his predecessor, and that swept governing parties out of office in Greece and Italy this month, Portugal in June and Ireland in February. 

In each case, the financial markets have forced the pace of events. As happened to Italy and Greece before it, Spain saw the effective interest rates on its new debt issues soar over the past week to heights not seen since the 1990s, before the introduction of the euro. The so-called risk premium demanded by investors for holding Spanish government bonds — compared with those of Germany, the soundest of the euro economies — briefly exceeded that of Italy on Friday. Together, they demonstrate a deepening skepticism that the euro zone can hold together and head off defaults by its weaker members. 

In the end, the Socialist government of Prime Minister José Luis Rodríguez Zapatero was undone by the evaporation of Spain’s economic boom after the world financial crisis took hold. When the government took office in 2004, the Spanish economy was growing by 3 percent a year, the budget was balanced and unemployment was low by Spanish standards. But when the financial crisis hit, property values and the construction industry collapsed, banks needed rescuing, economic growth slowed, joblessness soared (it is now over 21 percent), and government finances fell deeply into deficit. 

When Mr. Rajoy, 56, takes over as prime minister next month, he will bring little novelty to the Spanish political scene: he held senior posts in his party’s last government, from 2001 to 2004, and was defeated by Mr. Zapatero in the general elections of 2004 and 2008. 

In the closing days of the campaign, Mr. Rajoy called on Spaniards to make “a common effort” to confront what he described as “the most difficult economic situation that Spain has faced in the past 30 years.” He also insisted that Spain’s voice “needed to be respected in Brussels” during coming European negotiations over the debt crisis, adding, “We will stop being a problem and instead form part of the solution.” 

The threat of another recession and the magnitude of the euro debt crisis have made even supporters of the Popular Party question whether a center-right government can deliver the swift turnaround in Spain that the financial markets are demanding.