President Trump confirmed Friday that the U.S. was "cocked & loaded" to strike Iran last night, a move that could have accelerated the path to war.How we got here: The strike had been ordered in response to Iran's shooting down of a U.S. drone earlier this week, but the trend toward conflict began in earnest last year when the president announced that the U.S. would pull out of the internationally negotiated Iran nuclear deal.Leaving the dealMay 8, 2018: Trump announces that the U.S. will pull out of the 2015 Iran nuclear deal. That kicks off a "maximum pressure" campaign intended, at least officially, to yield a new, far more comprehensive deal. New rounds of sanctions are implemented in August, November and — most recently — April.Iran initially continues to comply with the deal, and the European signatories work desperately to save it.Bolton's warning May 5: National Security Adviser John Bolton issues a statement referring to impending Iranian attacks and announces a U.S. aircraft carrier is en route to the region.May 8: On the anniversary of Trump’s withdrawal, Iran announces it will increase uranium production.May 9: Acting Defense Secretary Patrick Shanahan presents plans for 120,000 U.S. troops to be deployed to the Middle East in the event of an Iranian attack, per the New York Times.May 10: The U.S. sends additional military hardware, including a warship, to the Middle East.First tanker attacksMay 12: Four oil tankers — two Saudi, one Emirati, one Norwegian — are attacked near the Strait of Hormuz. The U.S. later accuses Iran.May 14: Armed drones strike two Saudi pumping stations. Houthi rebels operating in Yemen claim responsibility.May 15: The U.S. orders a partial evacuation of its embassy in Baghdad, Iraq.New escalationsJune 13: With Japanese Prime Minister Shinzo Abe in Tehran and diplomacy apparently on the table, two more tankers — one Norwegian and one Japanese — are struck near the Strait of Hormuz.June 17: Iran announces that it will breach uranium enrichment levels under the 2015 deal in 10 days.June 17: The U.S. announces it will send an additional 1,000 troops to the Middle East.The drone attackJune 20: Iran shoots down a U.S. drone it says was in its airspace. The U.S. provides evidence it was over international waters.June 20: Trump approves strikes "on a handful of Iranian targets" but calls them off at the last minute, the NYT reports.June 21: Iranian officials tell Reuters they received a message from Trump warning of impending U.S. attacks and seeking dialogue as Trump confirms he felt the planned strikes were "not proportionate."Go deeper: Israeli officials say Iran won’t de-escalate without stronger U.S. response