In both the presidential and legislative elections, Marine Le Pen, the leader of the French far right, has suffered a blow so devastating that her National Front is in total disarray, as are all the traditional mainstream parties. Ideological lines have become confused in a major political realignment. Although it would be another leap into the unknown, the French now seem ready for all kinds of experimentation to replace a broken system. Their sulky, pessimistic mood has given way to “let’s turn the tables and start all over again.”

At the very least, a huge parliamentary majority should allow President Macron to pass the economic and labor reforms he is committed to in his “transformative” agenda. Such reforms are crucial to restart the Franco-German engine and rebalance the relationship between the two countries, itself essential to any European renaissance. German Chancellor Angela Merkel does not hide her enthusiasm for her new French partner, who has been equally keen to show how closely they are working together. These days, Paris-Berlin and Berlin-Paris flights have become crowded with civil servants heading to meetings.

A new sense of urgency is crossing the Rhine. Mr. Macron’s government is openly German-friendly; five of its members, including Prime Minister Edouard Philippe, speak the language fluently. The defense ministers of Germany and France, Ursula von der Leyen and Sylvie Goulard, speak the other’s language and have hit it off, with ambitious plans for European defense. On July 13, the day before Bastille Day, both governments will hold a joint cabinet meeting in Paris to discuss proposals to strengthen and further integrate the eurozone. The Franco-German rapprochement seems to extend beyond the leadership: The latest ARD-Deutschlandtrend poll, published on June 8, showed that 94 percent of Germans saw France as a trustworthy partner, while only 21 percent thought the same of Russia … and of the United States.

The last statistic points to another factor in Europe’s revival: Donald Trump. The American president’s belated profession of faith in Article 5 of the NATO charter on June 9 will not erase the damage done at the recent NATO and G-7 summits, and by his decision to withdraw from the Paris agreement on climate change. “We do have a problem with what he thinks, what he says and what he does,” a senior French official told me. “We must find ways of moving forward without the United States if they don’t want to come along. Merkel is right. The time has come to reform the E.U.”

French officials are quick to point out that partners on both sides of the Atlantic are in many ways interdependent and will continue to work together, in the fight against terrorism, for instance. Even on climate change, cooperation will find other routes, past the White House, to states and cities. “There are forces in the United States that we know we can rely upon,” Ms. Goulard, the French defense minister, said in Singapore on June 3, “and these forces will ultimately prevail.”

Most European leaders are waking up to this new reality. They don’t believe in the “adults in the room” tale anymore, once floated to enhance the influence of men they felt they could trust, like James Mattis and H. R. McMaster, to temper the instincts of an unreliable leader. In turn, those Americans will need to adjust to Europe’s own new reality.