https://www.vox.com/world/2019/7/8/18693297/us-iran-war-trump-nuclear-iraq

A deadly opening attack. Nearly untraceable, ruthless proxies spreading chaos on multiple continents. Costly miscalculations. And thousands — perhaps hundreds of thousands — killed in a conflict that would dwarf the war in Iraq.

Welcome to the US-Iran war, which has the potential to be one of the worst conflicts in history.

The Thursday night killing of Maj. Gen. Qassem Soleimani, who led Iranian covert operations and intelligence and was one of the country’s most senior leaders, brought Washington and Tehran closer to fighting that war. Iran has every incentive to retaliate, experts says, using its proxies to target US commercial interests in the Middle East, American allies, or even American troops and diplomats hunkered down in regional bases and embassies.

It’s partly why the Eurasia Group, a prominent international consulting firm, now puts the chance of “a limited or major military confrontation” at 40 percent.

But the seeds of conflict weren’t planted with Thursday’s airstrikes alone. Washington and Tehran have remained locked in a months-long standoff that only continues to escalate. The US imposed crushing sanctions on Iran’s economy over its support for terrorism and its growing missile program, among other things, after withdrawing from the 2015 nuclear deal last year; Iran has fought back by violating parts of the nuclear agreement, bombing oil tankers, and downing an American military drone.

The crisis has become more acute over the past week. An Iranian-backed militia killed an American contractor while wounding others in rocket attacks, leading the Trump administration to order retaliatory strikes on five targets in Iraq and Syria that killed 25 of the militia’s fighters. In protest, the militia — Ketaib Hezbollah — organized a rally outside the US embassy in Baghdad where some got inside the compound and set parts of it ablaze.

That led Secretary of Defense Mark Esper to tell reporters on Thursday that “if we get word of attacks, we will take pre-emptive action as well to protect American forces, protect American lives,” adding “the game has changed.” The US killed Soleimani hours after that statement, underscoring that change.