Donald J. Trump’s appeal to many voters in 2016 was that he was different, not a typical politician. Hillary Clinton was the face of stability, competence and experience—same old, same old. Mr. Trump was inexperienced but dynamic. A preponderance of voters in key states chose to take a flying leap into the unknown. They wanted an agent of change. What the country got was an instigator of chaos.

I do not know that we have ever before had a pyromaniac in the White House, somebody drawn to setting fires, who relishes creating trouble and cannot be trusted not to take a match to other people’s homes and even his own.

Trump voters wanted an agent of change. What the country got was an instigator of chaos.

Not content with having one full-blown crisis over nuclear weapons with North Korea, President Trump seems determined to bring about another with Iran. The effort to decertify the nuclear agreement in the face of a chorus of experts unanimously attesting to Iran’s compliance with the agreement is remarkable—and unnecessary.

Last week’s decision to recognize Jerusalem as the capital of Israel is equally gratuitous. Nobody, not even Israel, was clamoring for the United States to do this, yet Mr. Trump chose to ignore his own advisors and reverse long-standing U.S. policy, antagonizing the Palestinians, setting back his own efforts to revive the moribund peace process, provoking the Muslim world and stirring condemnation from the international community. Fourteen out of the 15 members of the U.N. Security Council, all but the United States, denounced the decision. The announcement has ignited protests and riots; as of this writing, four Palestinians have been killed and 50 injured.

Nobody, not even Israel, was clamoring for the United States to do this, yet Mr. Trump chose to ignore his own advisors.

All this for what? To honor a campaign promise? To satisfy donors such as billionaire Sheldon Adelson, the pro-Israel magnate close to Benjamin Netanyahu who gave millions to fund Donald Trump’s election? Mr. Adelson is said to have the president’s ear and to have pressed him to move the U.S. embassy to Jerusalem.

In announcing his decision to move to the embassy, Mr. Trump insisted he was simply “recognizing reality.” But it is a reality that violates international law and rewards Israel’s occupation. It is a reality that Israel has been steadily creating for 50 years by establishing Jewish colonies in the West Bank and East Jerusalem while harassing Palestinian Arabs living in the occupied territories with land expropriations, home demolitions and discriminatory policies intended to limit their population growth and hasten their departure from the Holy Land.

The United States is sending a message that might is the only right it recognizes and respects.

Some wonder if the announcement may be part of a long game the Trump administration is playing. But if there is a quid pro quo for recognizing Jerusalem as the capital of Israel, effectively accepting Israel’s position in one of the most sensitive issues in the Palestinian-Israeli conflict, it has yet to be presented. And the strategy that is rumored to be in the works is an outside-in approach, where Saudi Arabia cements its burgeoning alliance with Israel—one based on their mutual hostility to Iran—by dictating terms to the Palestinians, offering them a poison pill of a peace agreement, which, it is assumed, they will have no choice but to take.

Jerusalem plays a key role in the faith traditions of Jews, Muslims and Christians. For this reason, the United Nations wanted it to be an international city and has never recognized Israel’s unilateral declaration of sovereignty over the city, either before the 1967 war or after. The day before Mr. Trump issued his announcement, representatives of Jerusalem’s Christian community pleaded with him not to make it. Pope Francis condemned the decision after it was reported. While it may play well with members of the Christian evangelical community who fantasize about the Second Coming of Christ, those interested in peace cannot but be disheartened and dismayed.

By ignoring U.N. resolutions on Israel and Palestine, the United States is sending a message that might is the only right it recognizes and respects. It is a call to arms for the Palestinians, a signal to them that to look to the international community for recourse is futile, that the only way their needs will be addressed is through brute force. It is a signal to Israelis as well, a green light to take what land they want without fear that they will ever need to return it or be accountable for the circumstances in which they took it. Some elements within Israel may find in its toothless acquiescence to Israeli expansionism encouragement for worse deeds—Palestinian expulsion or transfer.

Perhaps “the ultimate deal” in the Middle East that Trump promises will obviate or negate the dangers of his recognition of Jerusalem as Israel’s capital. Or perhaps the “ultimate deal” is no deal at all, and, like he has with his senseless policy on Iran, President Trump will have recklessly stirred the pot with no good end in sight.

Margot Patterson has written for a variety of newspapers and magazines in the United States and abroad. Most recently, she worked for the National Catholic Reporter for seven years as Senior Writer and then Opinion and Arts Editor. She lives in the Kansas City area and is the author of Islam Considered: A Christian Perspective (2008).