President Trump has deployed them against foreign adversaries. He has used them with publicly traded companies. And he has even, briefly, slapped them on American allies.

So it was little surprise this week when — dismayed with Iraq’s recent parliamentary vote to expel U.S. troops from the country — Trump reached for one of his favorite means of retribution: sanctions.

“We will charge them sanctions like they’ve never seen before ever,” Trump told the reporters traveling with him on Air Force One after the Iraq vote over the weekend. “It’ll make Iranian sanctions look somewhat tame. If there’s any hostility, that they do anything we think is inappropriate, we are going to put sanctions on Iraq — very big sanctions on Iraq.”

And just days later, on Wednesday, Trump announced unspecified additional sanctions against Iran in response to that country’s missile strikes against military bases housing U.S. forces in Iraq.

Three full years into Trump’s presidency, sanctions have emerged as one of his preferred diplomatic tools — used as both negotiating chips and punishment. His Treasury Department has designated or imposed sanctions on more than 2,800 individuals, entities, vessels and aircraft since his inauguration, in a marked increase from his predecessors.

And Trump imposes sanctions much like how he governs — using them aggressively if haphazardly, as both unfulfilled threats and fully formed censure and often delivered with great fanfare and bluster.

Shortly before implementing and then reversing sanctions on Turkey in October, for instance, the president saber-rattled against the NATO ally over Twitter, writing, “If Turkey does anything that I, in my great and unmatched wisdom, consider to be off limits, I will totally destroy and obliterate the Economy of Turkey (I’ve done before!).”

Allies and advisers say that for Trump, sanctions can be particularly effective because even the mere mention of them can have a deterrent effect.

“He’s a man of action in a town of talk, and sanctions are a preferred tool in a well-stocked diplomatic arsenal,” said Kellyanne Conway, counselor to the president. “The president’s sanctions are not an end but a means to an end. It’s both carrot and stick. It’s a stick for punishment for reckless threats or actions. It’s also an incentive, a promise of possible economic development and improvement.”

Richard Nephew, the program director at Columbia University’s Center on Global Energy Policy and the author of “The Art of Sanctions,” added that the president is something of a sanctions aficionado.

“Trump has taken quite a shine to sanctions,” Nephew wrote in response to emailed questions. “He threatens them with gusto and frequency.”

The reasons, Nephew added, are threefold. First, Trump, a former businessman, “sees money as a universal source of value” and appreciates that the direct ramifications of sanctions are financial. Second, sanctions appeal to Trump’s general aversion — albeit with certain notable exceptions — to using force, allowing him to impose his will with what he views as minimal U.S. risk or investment. And third, sanctions satisfy his “ ‘do something’ impulse,” especially when it comes to intractable foreign policy problems.

A senior administration official agreed, emphasizing that as a former Manhattan real estate developer, Trump understands the power of financial penalties and withholding money. A second person familiar with Trump’s handling of sanctions said the president enjoys the position of leverage that comes from presiding over the world’s largest economy. Both also stressed that Trump appreciates the nonkinetic nature of sanctions, placating a commander in chief at once leery of foreign entanglements but eager for grand displays of power. The two people spoke on the condition of anonymity to share candid assessments.

Though the use of sanctions has steadily increased every year since the Sept. 11, 2001, terrorist attacks, in part as a means of disrupting and penalizing terrorist organizations and rogue nations, Trump has significantly expanded the use of sanctions and designations since taking office. In 2018, for instance, Treasury’s Office of Foreign Assets Control imposed sanctions on more terrorists and supporters of terrorism than in any other of the past 15 years, said Treasury Deputy Secretary Justin G. Muzinich.

“Treasury strategically deploys a broad range of economic authorities to combat terrorist financing, money laundering, proliferation finance, human rights abuses, drug trafficking, corruption and other illicit finance and national security threats,” Muzinich said in a statement.

The most active sanctions programs, in order, are Iran, Russia, North Korea, Venezuela and counterterrorism, Muzinich said.

Adam Smith, a former sanctions official under President Barack Obama who is now a partner at the law firm Gibson, Dunn & Crutcher, said that according to statistics he and the firm have tracked, Trump is averaging more than 1,000 new designations per year, compared with about 500 under Obama and about 430 under George W. Bush.

Another difference, Smith said, is how personally invested Treasury Secretary Steven Mnuchin is in sanctions policy. Mnuchin has said that he spends “probably over 50 percent” of his time on sanctions and national security issues, and Smith also noted how frequently Mnuchin personally delivers sanctions news. In his first year at Treasury, Mnuchin personally announced sanctions about two dozen times, compared with just a handful of times for both of Obama’s treasury secretaries throughout their tenures, Smith said.

Sanctions are in some ways “uniquely designed, and unwittingly so, for someone of Mr. Trump’s background and governing style,” Smith said.

“You have a president who arrived in office with no governmental experience, a limited network of friends in Congress and the bureaucracy, and a desire to move quickly and unilaterally,” Smith said. “Sanctions have allowed the president to do what he used to do in the private sector — act rapidly and without the need to consult or receive permission.”

Similarly, Elizabeth Rosenberg, a former senior sanctions adviser under Obama who is now a senior fellow at the Center for a New American Security, said Trump favors sanctions because he “doesn’t want to go to war and wants to be a strongman, and these are words that make him and others feel as though he’s issuing powerful and formidable threats — and he has used them, so they’re not empty.”

Since becoming president, Trump has mentioned “sanctions” in 34 tweets, pecking out bite-sized warnings to a host of countries — “highest-level sanctions” (Cuba), “the most biting sanctions ever imposed” (Iran), “maximum sanctions and pressure” (North Korea), and “Big sanctions” (Turkey).

“Sanctions are appealing to the president because they appear to him and to many others as a policy option somewhere in the realm between talk diplomacy on the one hand and military force on the other, and because they are generally and unfortunately perceived to be costless,” Rosenberg said. “I don’t think that they are costless.”

Trump also appreciates the unilateral nature of many sanctions. After backing away from the October sanctions against Turkey, Trump seemed to relish his power to impose them — and circumvent Congress if necessary.

“Well, sanctions won’t be necessary because Turkey is doing what they’re doing,” Trump said. “I didn’t need Congress for sanctions because I can do sanctions that are tougher than Congress. And I was prepared to do that.”

When it comes to Iraq, senior administration officials have begun drafting sanctions against the U.S. ally, although some in the administration remain skeptical Trump will actually implement the punishment.

But outside experts said merely dangling the prospect of sanctions epitomizes Trump’s general approach to the tool.

“When Trump said [Sunday] he was going to use sanctions against Iraq, he didn’t outline a theory of the case, and so it felt more like, ‘You can’t break up with me; I’m breaking up with you,’ ” Rosenberg said.

Said Smith: “Sanctions have become a reflex. If you don’t like what a country is doing, you threaten sanctions and maybe then impose them.”