John Bolton, President Trump’s national security adviser, elicits strong feelings — both pro (from Fox News viewers) and con (from everyone else). In truth, his impact has been more equivocal than many (including me) had expected. He has actually been a force for good on North Korea policy — and a dangerous, destabilizing influence on Iran policy.

Bolton is skeptical of dealing with dictators, but he knows he can’t simply oppose negotiations with North Korea given how much political capital his boss has invested in those unproductive talks. Even after Kim Jong Un tested short-range missiles last week, Trump tweeted, “I am with him.” Bolton would have hyperventilated on Fox News if it had been President Hillary Clinton proclaiming her devotion to a vile tyrant who was responsible for the death of an American student. But because it’s Trump talking, Bolton has to bite the tongue he hides under his massive mustache and work behind the scenes to prevent a one-sided deal in which the United States commits to lifting sanctions on North Korea, and even pulling U.S. troops out of South Korea, in return for empty promises of “denuclearization” from Pyongyang.

Bolton has often cited the “Libya model” of denuclearization. Given that Libyan leader Moammar Gaddafi was overthrown and killed, Kim is not keen on such a deal. Bolton no doubt urged Trump to walk away from the Hanoi summit when Kim would not offer full disarmament. The national security adviser has since demanded that North Korea provide a “real indication . . . that they’ve made the strategic decision to give up nuclear weapons” before the United States agrees to a third summit.

Little wonder, then, that North Korea has slammed Bolton as “dim-sighted” and that Trump himself has on occasion disowned his national security adviser. Bolton appears to be playing the long game, hoping that Trump eventually will tire of his unrequited romance with Kim and return to “fire and fury” — perhaps even by launching the preventative attack that Bolton advocated shortly before being appointed to his current position in March 2018.

Starting Korean War II would be a horrible mistake. For now, however, Bolton has been a positive influence by preventing Trump from making excessive concessions to a dictator that he’s in “love” with.

Bolton’s influence over Iran policy has been more worrisome. Given his long record of advocating military action against Iran, Bolton sparked concerns at the Pentagon last year that he could be trying to precipitate a conflict when he demanded military options against Iran. Those concerns were hardly assuaged when in February, on the 40th anniversary of the Iranian revolution, Bolton posted a video warning the ayatollahs: “I don’t think you’ll have many more anniversaries to enjoy.”

Trump has been more receptive to Bolton’s hawkish guidance on Iran than on North Korea. Trump jettisoned President Barack Obama’s nuclear deal — far more restrictive than any agreement he is ever going to get from North Korea — even though Iran has been abiding by it. Now, at Bolton’s urging, Trump is ramping up sanctions on Iran, rescinding waivers that had allowed some countries to buy its oil, and designating the Iranian Revolutionary Guard Corps a terrorist organization.

But Trump still won’t go as far as Bolton wants. In September, Bolton said that U.S. troops would remain in Syria as long as Iranian forces did. Three months later, Trump announced an immediate exit from Syria, which would have handed that country to Iran and Russia. Bolton pretended that Trump agreed with him, and somehow convinced the president to maintain a smaller garrison in Syria.

The U.S. confrontation with Iran took a more ominous turn on Sunday night, when Bolton announced that, “in response to a number of troubling and escalatory indications and warnings,” the Pentagon would be rushing an aircraft carrier task force to the Persian Gulf. “The United States is not seeking war with the Iranian regime, but we are fully prepared to respond to any attack,” Bolton said.

This is the kind of bellicose action that Jim Mattis might have blocked while he was still secretary of defense. But with Mattis gone, Bolton is getting his way.

The administration leaked word that it had received “specific and credible” information, apparently from Israel, about Iranian threats against U.S. forces in the region. Administration officials have also leaked word to friendly journalists about supposed Iranian ties with al-Qaeda. All of this information could be accurate, but it’s hard to take at face value. The administration lies at a record-setting pace (Trump just recorded his 10,000th falsehood), and Bolton himself was credibly accused of twisting intelligence in the past to justify U.S. action against Iraq and Cuba. The current hyping of the Iranian threat reminds some analysts, such as my colleague Steven A. Cook, of the run-up to the Iraq War — a terrible mistake that Bolton still defends.

The big difference is that Trump is far more reluctant to be drawn into a Middle East war than George W. Bush was. Bolton, therefore, may be trying to provoke Iran into striking first. A Tonkin Gulf incident got us into one war. Will a Persian Gulf incident get us into another?

When it comes to North Korea, Bolton acts as a useful check on Trump’s desire to win a Nobel Peace Prize at any cost. In Iran, however, I fear that Bolton is trying to instigate a costly conflict that could engulf the entire Middle East.

Read more: