In last Sunday’s European parliament elections there were two earthquake results in France. The first is the breakthrough of the far-right nationalist, anti-EU, anti-immigrant National Front party (FN). The second is the overwhelming defeat of the governing Socialist party (PS) of President François Hollande. The French Socialists’ failure, however, goes deeper in history. Their perennial weakness as a party has characterized French politics for a long time.

Marine Le Pen’s FN, the flagship of European far-right politics, won 25 percent. The Socialists collapsed to 14 percent, following an already dismal showing in March’s municipal elections. But this isn’t all: As president, Hollande has been polling below 20 percent for months, the worst ever in the Fifth Republic and, on reflection, a really astonishing failure.

After two years of dismal governance, the French Socialists have lost legitimacy almost completely, yet Hollande and his parliamentary majority have three more years to run. It’s a classic story: ringing ideological left-wing chimes in electoral campaigns, then consternation and confusion when generous intentions, ignorance of economics and lack of political determination end in a blind alley.

When Charles de Gaulle founded the Fifth Republic in 1958, the French Socialists already had a checkered history. In the 1930s Léon Blum, the admirable socialist humanist, failed to mobilize France against the Nazi menace. In the Fourth Republic, 1946 to 1958, the Socialists continued to flounder, intimidated by the French Communists on the left and Gaullists on the right. They were, in a local joke, the slice of ham in a sandwich and getting thinner all the time.

Finally, after 23 years, with the tenacious François Mitterrand as their candidate, they won the presidency and parliament in 1981. When Mitterrand left power in 1995, the PS’ future seemed the natural left-wing governing party in a stable left-right alternation of power. But the party elite failed to produce leaders of genuine stature and determined convictions.

In 1997 the Socialists unexpectedly won a fluke election when President Jacques Chirac mistimed dissolution of parliament. Then, in 2002, at the end of five desultory years in office, the incumbent Socialist prime minister Lionel Jospin was astoundingly defeated in the first round by Marine Le Pen’s father, the original far-right rogue, Jean-Marie Le Pen, who had founded the FN. (Le Pen lost to Chirac in the runoff by fully 60 percent.)

“Embarrassing” for France is too weak a word. That Jean-Marie Le Pen got to the runoff amounted to Socialist failure to protect the country’s politics from a rising nationalist-racist fringe that continues around Europe today.

Adding it up, until Hollande’s victory in 2012, the Socialists elected only one president since 1958, the exceptional Mitterrand. And he came from outside, joining the party only in 1969, at the age of 51.

Why can’t the Socialists do better? Why don’t they produce truly ambitious, battle-hardened candidates with fire in the belly? (In 2007 their candidate was the equally inexperienced Ségolène Royal, Hollande’s domestic partner for 30 years and mother of his four children. And let’s not forget the scandal of their initial likely candidate for 2012, Dominique Strauss-Kahn.)

What can President Hollande possibly do now to rescue the situation? He has one trump card that few would expect of him: Tell Prime Minister Manuel Valls to try for an unprecedented Grand Coalition that would ally the Socialists, the UMP (21 percent) and the centrist Modem party (10 percent) — that is, 45 percent in the European election. In a parliamentary election that coalition would produce a solid majority of seats with new legitimacy. Grand coalitions can govern quite successfully. Germany is the best example. But besides a strong leader, it needs a sense of mutual respect and loyalty among the parties, meaning the French conservatives and centrists must also admit that this time the jig is really up on politics as usual, including them. This would begin to restore France’s credibility in wider Europe.

With effective government Hollande could reverse France’s slide to the right. He could create conditions for the serious economic reforms that both right and left parties have failed at consistently. He could encourage the private sector, foster economic dynamism and reverse the unprecedented collapse of foreign investment. A Grand Coalition with a combative leader — Valls is that man — could confront the French street (i.e., the perennial mass protests and strikes that intimidate governments afraid of not being reelected). The army of French unemployed might start to shrink, which is especially important for young people.

Hollande would look patriotic having made a kind of Gaullist gesture, rising above party politics. A Grand Coalition would be a new kind of “cohabitation” in the French system, different from a president of one party facing a contradictory prime minister and parliamentary majority. Hollande would demonstrate the Constitution’s flexibility as a basis of forming governments.

Above all, Hollande would be responsible for something new in France today: success and optimism.