BEIRUT -- Iran won't be "alone" in the event of war with the U.S., having significantly expanded its footprint over the past decade -- from Lebanon and Syria to Iraq, Yemen, and the Gaza Strip, finding and developing powerful allies in conflict-ravaged countries.
It has used groups like the Lebanese militant Hezbollah group to strike its regional foes. These allies could be mobilized if the latest tensions with Washington lead to an armed conflict, dramatically expanding the battlefield.
Then there is the Palestinian militant Hamas group, and also Yemen's Shiite rebels, already at war with Iran's rival Saudi Arabia.
Also, Iran has trained, financed, and equipped Shiite militias in Iraq that battled U.S. forces in the years after the 2003 invasion and remobilized to battle the Islamic State group a decade later.