The next drama after the re-election of Emmanuel Macron as president of France is what the cognoscenti call the “third round.” Mr. Macron, falling short of a majority in the first round, defeated Marine Le Pen in the second round. The third round is the election of the National Assembly, which our Paris leg, Michel Gurfinkiel, has been warning could deliver an astonishing result.

This arises not only because, Mr. Gurfinkiel reminded us two weeks ago, it is “vital for any president, in any country, to engage with a friendly legislature.” It turns out that under the constitution of the Fifth French Republic, Mr. Macron would be compelled to pick a prime minister and cabinet from the National Assembly’s majority. That gives the French president “quasi monarchical” powers when things go his way.

Then again also, too, it’s by no means certain these things are going to go Mr. Macron’s way when voters return to the polls for the parliamentary election June 12. He won the presidency by a fine margin — 59.5 percent to Ms. Le Pen’s 41.5 percent. That margin, though, is narrower than the 66.1 percent to 33.9 percent margin by which he defeated her in the 2017 election that gave him his first term.

Mr. Macron’s victory this year was by a slightly wider margin than polls predicted two weeks ago. Yet it’s not so unambiguous as to remove suspense from the drama shaping up in the vote for the Assembly. This was underscored by Ms. Le Pen, who was quoted by USA Today as declaring that “the game is not completely over” and by the Times as saying voters want a “strong counter power to Emmanuel Macron.”

Ms. Le Pen appears to be talking about what our Mr. Gurfinkiel has been calling a “Resentment Coalition,” or a Red-Black Coalition combining the votes of the rightists who backed Ms. Le Pen and the leftists who backed Jean-Luc Mélenchon. A close runoff for president, Mr. Gurfinkiel has written, “might enable the whole Resentment Coalition to enter en masse the National Assembly or even to dominate it.”

There are, we gather, signs that it would be wise to take nothing for granted. In the run-off Sunday, the vote in some precincts dominated by the left — Mr. Gurfinkiel has called Mr. Mélenchon France’s Jeremy Corbyn — went strongly in favor of Ms. Le Pen. If that kind of showing is carried over into the Assembly election in June, Mr. Macron could have a bitter foe for prime minister. 

It wouldn’t be the first time that’s happened, by any means. Between 1986 and 1988, President Mitterrand, a socialist, had to “cohabit” with a rightist premier, Jacques Chirac. And again, between 1993 and 1995, with a particularly brilliant conservative, Édouard Balladur. Once Mr. Chirac became president in his own right, he ended up being forced to share power with a socialist premier, Lionel Jospin.

We don’t remember any of those being quite as bitter or dramatic as French politics could become were Mr. Macron to be confronted with an Assembly dominated by a combination of Le Pen nationalists and Mélenchon leftists. Plus also, too, is the fact that Mr. Macron is not a particularly popular president in the first place. His approval rating has been lurking at something like 40 percent — or lower.

Our own Democrats are trying to spin that as an auspicious fact for Mr. Biden. “President Macron appears to have secured a double-digit victory over Le Pen, at a time when his approval rating is 36%. Hmmm….,” President Biden’s chief of staff, Ron Klaim, just tweeted. Then again, we might have the American version of divided government before the next presidential election.

The way divided government has often worked in France is that the president focuses on foreign affairs and the premier on domestic matters. Once, when Prime Minister Balladur was in New York on a visit, we tried to draw him out against President  Mitterrand on a foreign matter. It was a vain effort. It seems that French political feuding did stop at the water’s edge. So even in a worst case scenario, Mr. Macron could have some fun.