“Bon jour,” was how an eager, cheerful reporter greeted Linda Thomas Greenfield shortly after the new American ambassador presented her credentials to the United Nations Secretary General.

It was an apt welcome to a building at the heart of midtown Manhattan, where even the elevators audibly announce the floors in French before they helpfully add an English translation. Ms. Thomas Greenfield spoke English in that short press encounter last week, but at Turtle Bay there was a universal sigh of relief that a kindred spirit has finally replaced the Trump-era UN-averse diplomats.

“We heard that she’s a professional,” said the Russian deputy UN ambassador, Dmitry Polyanskiy. “She’s one of us, let’s put it this way.”

It would be wrong to suggest that Ms. Greenfield Thomas is a “Russian puppet,” as a former president was often accused of being (and would have undoubtedly garnered endless headlines if a Russian official called him “one of us”). In perfect Turtle Bay pitch, the Louisiana-born ambassador told reporters that sure, “we have our differences” with Russia, but that “we also have areas where we hope to be able to cooperate” and “it’s incumbent that we find ways to find common ground.”

A 35-year State Department veteran, Ms. Thomas Greenfield is an Africa specialist known to fans for “Gumbo diplomacy.” To judge from her UN debut, she’s a fan of multinational cooperation. In a Monday press conference marking America’s assumption of the Security Council presidency for the month of March, she hit all the sweet spots:

We are back at the world Health Organization, she said. We rejoined the Paris Accord on climate change. We renewed support to UN agencies that the previous administration left or cut off financially. America is once more running for a seat on the Human Rights Council, which Presidents George W. Bush and Donald Trump shunned.

Other decisions to “lead by example,” she said, are ending Trump-era horribles like the “Muslim ban,” launching a government-wide initiative to advance racial equity, protecting “Dreamers,” reversing a “ban on transgender individuals serving in our military,” and restoring “our refugee admissions program.”

In other words, as Ms. Thomas Greenfield put it, “America is once again shining our light of liberty at those who need it most.”

Turtle Bay diplomats, as well as much of its press corps, have longed for such a UN-friendly American face, and Ms. Thomas Greenfield is just as eager to pal up to them. Even America’s worst adversaries get more of an open hand than a clenched fist. Our relations with Communist China are “very complex,” she said, but there are “some areas” that we can work together, such as climate change.

The Iranian regime most recently violated the nuclear deal and announced Monday that it would refuse to meet with Europeans on renewal of that deal, known as the Joint Comprehensive Plan of Action. Sure enough, Iran was high on the agenda in her meetings with the 15 Security Council members over the weekend, Ms. Thomas Greenfield said.

The new American envoy hasn’t “yet met with the Iranian permanent representative” to the UN, she told one reporter. Will she? When pressed she said she’s awaiting instructions from Washington on authorizing such a meeting.

Last year America voided the Security Council resolution that backed the nuclear deal, using that resolution’s self-destruct “snapback” option. Even before Ms. Thomas Greenfield arrived here, though, a Biden official announced a reversal. With that, America now agrees with China, Russia, and the Europeans that Tehran can legally sell and buy arms on the open market — first of many “sunset” clauses baked in that resolution that incrementally removes sanctions imposed on the Iranian regime.

Such is the nature of Turtle Bay-driven policies. Never signed as a treaty, the only legal writ of the/nuclear deal is the Security Council resolution. Endless violations of the JCPOA are now openly flaunted by the Tehran regime but at the UN, where Iran-allied Russia and China and business hungry Europeans assume oversized powers, such violations count for little.

The mullahs may tease us endlessly before rejoining the nuclear deal, but Security Council resolutions are hard to rescind. So we have no choice but to let sanctions “sunset,” one at a time, until, at the end of this decade, the regime can legally boast of as many deliverable bombs as it chooses.

Ms. Thomas Greenfield doesn’t see any of this as giving in to the world’s lowest common denominator. Rather, as she boasted, “there’s no problem this body cannot solve if we decide to tackle it together.” Much good will happen, she reckoned, if we “set aside our differences, search for common ground and do right by the world.”

That “doesn’t mean we won’t disagree,” she said. “It doesn’t mean we stop standing up for our values, or for our allies, for human rights, or for our basic interests. It does not mean we do not stand for the American people, but, in fact, it means the opposite.”

Well, it looks like we have four years to learn how working together with even our worst enemies will benefit the American people. Or as the French might say, it’s bon jour in America again.

Twitter @bennyavni