Donald Trump presented his “Iran strategy” on October 13, arguably delivering the most negative speech on Iran ever delivered by a U.S. president. In his nine months in office, Trump has arguably generated more anti-Americanism among Iranians than the political elite of the Islamic Republic has achieved in almost four decades. The nuclear agreement may not be touched, let alone torn apart, at this point. But the president has created an unnecessary crisis over its implementation. Such behaviour by the U.S. is exactly what causes alarm bells to start ringing in Iran’s security establishment. And what does Iran do when it feels threatened? It props up its deterrence capacities—namely, its ballistic missile program, its regional alliances, and tough talk about acts of retaliation in case the U.S. should make ‘further mistakes. To put it more bluntly: current U.S. rhetoric will be a catalyst of Iran’s missile program and Iran boosting its support for its allies in the region on both the state and non-state levels. This will concern for Iran’s neighbours, and they will—surprise, surprise—seek to invest further into their respective military apparatuses. This is how a regional arms race is encouraged. The formula “divide and conquer” has turned into “divide and sell” given the massive weapons sales the U.S. has secured to Saudi Arabia, Israel, Kuwait and Qatar over recent years. The more threatened Iran feels, the more it will deem it necessary to show its (perceived and real) enemies that it can hurt them effectively. All this will lead to an intensified sense of insecurity in an already volatile and insecure region. This is exactly why Donald Trump’s approach is reckless.