After three difficult years, armed groups loyal to Tehran appear to be bouncing back across the Middle East, reinforcing Iran’s leverage in its war with the United States and Israel.

For decades, experts say, these groups played a key role: acting as a powerful deterrent against direct attacks on Iran. The “Axis of Resistance” – an anti-Israel and anti-Western alliance of regional militias backed by the Islamic Republic – was, however, significantly weakened by Israel’s large-scale military response to the 2023 Hamas attack and the regional repercussions that followed.

It was when this axis was in a weakened state that direct conflict between Israel, the US and Iran erupted. Today, however, several armed groups allied with Tehran are back to pressuring Iran’s foes by opening new fronts that complicate the war and threaten to choke the global economy.

“The Axis (of Resistance) worked very well for more than two decades, helping ensure there was no attack on Iran while these groups extended their influence within their own territories,” Trita Parsi, executive vice president of Quincy Institute for Responsible Statecraft, told CNN. “Once they were weakened, Iran paid the price by having both the US and Israel attack it.”