“Some will celebrate, some will mourn, some will seek revenge,” said an Iraqi official as word spread in Baghdad on Thursday night that the Iranian general Qassem Soleimani had been killed in an American airstrike. But there is little question, the official added, that U.S. relations with Baghdad are in “real jeopardy.”

The consequences may not come quickly or directly. But they could be enormous. At their most dire, this strike may be the beginning of a much wider war in the Middle East—perhaps even the all-out war with Iran that Trump has said he wants to avoid.

In a tweet early Friday, Trump sounded a bellicose note: “Iran never won a war, but never lost a negotiation!”