President Trump delivers his State of the Union address at the Capitol on Tuesday. (Doug Mills/the New York Times via AP, pool)

Throughout his tenure, President Trump has directed rhetorical barbs at Iran’s regime, including in Tuesday’s State of the Union address, during which he said: “My administration has acted decisively to confront the world’s leading state sponsor of terror, the radical regime in Iran. . . . To ensure this corrupt dictatorship never acquires nuclear weapons, I withdrew the United States from the disastrous Iran nuclear deal.”

That’s mild compared to last year’s tweet putting Iran’s president on notice:

Taken on their own, his words aren’t a total departure from those of other politicians: In his 2002 State of the Union speech, President George W. Bush marked Iran as part of an “axis of evil.” In 2007, Sen. John McCain (R-Ariz.) quipped, “Bomb Iran? Bomb, bomb, bomb. . .” to the tune of the Beach Boys’ “Barbara Ann.”

But as president, Trump has been more consistent with his aggressive posture toward Iran than he has on many other issues. In his first two years in office, the changes he has made to his Cabinet, the disregard he has shown for diplomacy and his choices in the Middle East all conspire to make war with Iran a growing danger.

First, there are now fewer voices of restraint on Iran inside the White House. Former national security adviser H.R. McMaster, no dove on Iran, tried to persuade Trump to remain a party to the Joint Comprehensive Plan of Action (JCPOA), known as the Iran nuclear deal. Trump pulled out of the 2015 deal shortly after McMaster left the Trump White House. McMaster’s replacement is John Bolton, a figure who has advocated military action in Iran, including in a 2015 New York Times op-ed titled, “To Stop Iran’s Bomb, Bomb Iran,” in which he argued: “Time is terribly short, but a strike can still succeed.”

With the recent departure of Defense Secretary Jim Mattis, Patrick Shanahan is now acting secretary at the Pentagon. His background is in industry, not in working the levers of national security policy or bureaucracy. Where Mattis was, in some instances, able to rein in the president’s instincts, Shanahan has said that the Pentagon is “not the Department of No” for the White House.

Second, when the president abandoned the Iran nuclear deal, he also abandoned the diplomatic infrastructure that made it possible. With the four other permanent members of the United Nations Security Council and Germany still abiding by the deal, along with Iran, the United States is now operating on a separate track from several powerful partners. Without them, the United States has limited ability to build meaningful pressure against Iran.

Secretary of State Mike Pompeo knows this only too well, having scheduled a summit in February to initiate a new “pressure campaign” against Iran, only to have select American allies signal they would not attend if the summit was only focused on Iran. Trump may tout new sanctions, as he did in his State of the Union, but our allies recognize the accuracy of the recent testimony of Director of National Intelligence Daniel Coats, who reported to Congress that our intelligence services “do not believe Iran is currently undertaking” the key “activities we judge necessary to produce a nuclear device.”

Third, continued volatility in the Middle East presents additional risks. The president has important allies in the region, including Saudi Arabia’s monarchy, which has long viewed Iran’s regime as its nemesis. In recent years, the Saudi crown prince and defense minister, Mohammed bin Salman, has shown he is willing to confront Iran militarily by prolonging the horrific war in Yemen against Iranian-backed Houthis, and by organizing an ill-conceived blockade against Qatar in an effort to pressure Saudi Arabia’s Persian Gulf neighbors to cut ties with Iran.

Trump maintains that Saudi Arabia is a “great ally in our very important fight against Iran.” He demonstrated his fealty to the crown prince by refusing to condemn him for the brutal killing of Washington Post contributing columnist Jamal Khashoggi at the Saudi Consulate in Istanbul on Oct. 2.

Fourth, Israel’s government has long-standing and genuine concerns about Iran, not the least of which is that Iranian forces, and elements of the Lebanese Shiite militant group Hezbollah, an Iranian proxy, are fighting next door in Syria on behalf of President Bashar al-Assad. While Israel’s military response has largely been targeted and measured, its strikes in recent weeks against Iranian and Iran-supported forces have become more aggressive.

In the run-up to Israeli elections this spring, countering Iran and keeping close ties with Trump have been at the center of Prime Minister Benjamin Netanyahu’s campaign to remain in power: His party just unveiled a huge billboard showing Trump and Netanyahu engaged in a tight grip-and-grin. Trump also benefits from the relationship: He enjoys strong support with his Republican base for his handling of relations with Israel and for delivering on his promise to move the U.S. Embassy from Tel Aviv to Jerusalem.

What happens, though, if violence in Syria further escalates and Iran strikes back in response to Israeli action against its proxies in Syria or in Lebanon? How will Trump respond if Netanyahu asks for U.S. military support?

There are other scenarios that could lead to a dangerous escalation: What if Iran follows the United States, exits the JCPOA, then brazenly races to build nuclear weapons? What if American troops leaving Syria, or remaining U.S. forces in Iraq, are provoked by Iranian or Iranian-backed forces? What happens if Trump simply decides he is fed up with Iran’s malign conduct in the region? The slightest provocation could provide an excuse.

Late last summer, Pompeo condemned Iran for rocket attacks near the U.S. Embassy in Baghdad and the U.S. Consulate in Basra. This week, Foreign Policy reported on a 2017 incident in which U.S. forces chose to stand down from an order to strike Iranian-backed forces traveling through southeastern Syria — transporting, apparently, a “port-a-potty” — an order the Americans believed was outside the scope of their rules of engagement. The incidents underscore that parts of Syria and Iraq remain a crowded battle space, leaving ample room for miscalculation.

Trump would not be the first president acting precipitously to lead the country into conflict. American history is replete with examples of presidents making ill-advised or inflated cases for war. It happened after an explosion aboard the USS Maine in 1898, after an incident in the Gulf of Tonkin in 1964 and in the run-up to the 2003 Iraq invasion. It can happen again.

Before Trump involves our armed forces in response to any reported provocation, Congress, the press and the public should demand that the intelligence surrounding that action is unassailable; the enemy accused of the violation clearly identifiable; the timing for a military response justifiable. There must not only be a political rationale for intervention, but a legal one as well. And there needs to be a long-term strategy, not merely an impulse pushed out in 280 characters.