The fall of Bashar al-Assad's regime in Syria has caused a major upheaval in the regional balances of power in the Middle East, strengthening the positions of Iran's rival powers such as Turkey and Israel. This development comes at a time when Iran is already under pressure, just weeks before Donald Trump's return to the White House.

Since the U.S. invasion of Iraq in 2003 and the overthrow of Saddam Hussein's regime, Tehran’s sworn enemy, Iran has solidified its influence in Baghdad through pro-Iranian religious parties that took power. The rise of the Islamic State (ISIS) in 2014 further reinforced this grip, notably through the militias of the "Hashd al-Shaabi" (Popular Mobilization Forces), created under Iranian supervision to fight ISIS in Iraq and Syria.

Alongside Syria, Iraq, Hezbollah in Lebanon, Hamas in Palestine, and the Houthis in Yemen, Iran has shaped what is known as the "axis of resistance," a strategic alliance aimed at containing Israel through an advanced defense policy.

However, the recent Israeli war on Gaza and Lebanon, coupled with two waves of strikes on Iranian soil, has changed the rules of the game. Hezbollah and Hamas have suffered heavy losses, and the fall of Assad's regime has definitively removed Syria from the strategic equation of the "axis of resistance," depriving Iran of key geopolitical cards and raising the possibility of new pressures to reduce its influence in Iraq.

Since the beginning of the armed Syrian factions' offensive against Aleppo on November 27, followed by the fall of other Syrian cities up to the outskirts of Damascus, one question remains: why didn’t the forces of "Hashd al-Shaabi" support the Syrian army?

According to some sources, Tehran allegedly asked Iraqi Prime Minister Mohammed Shia al-Sudani to authorize the deployment of "Hashd al-Shaabi" in Syria, but he reportedly refused any military engagement, limiting himself to declaring a state of alert on the Iraq-Syria border for fear that ISIS might take advantage of the chaos to launch attacks in Iraq.

Other accounts suggest that, faced with the Syrian army's unwillingness to fight the rebel factions, Iran chose not to insist and to wait for the situation to evolve. The visit of Iranian Foreign Minister Abbas Araqchi to Damascus after the offensive reportedly confirmed this: the Syrian army did not want to engage in a bloody war, leaving Assad to his fate.

Simultaneously, Israel reportedly issued multiple warnings against the potential entry of Iraqi or Iranian forces into Syria. Israeli aircraft even allegedly prevented two Iranian civilian planes from landing at Damascus airport, suspecting them of transporting members of the Revolutionary Guards or Iranian weapons.

The shift in the balance of power in favor of the Syrian opposition reportedly pushed al-Sudani to engage in diplomatic efforts with Ankara, Moscow, Tehran, and Gulf countries to negotiate a political transition in Syria.

In this context, Iraqi Shiite leader Muqtada al-Sadr reportedly issued a strong warning against any Iraqi military involvement in Syria. Opposed to Iranian influence, al-Sadr had refused to form a government with Tehran's allies after the last parliamentary elections, preferring his bloc to resign en masse from parliament.

With the strategic loss of Syria and the weakening of Hezbollah in Lebanon, Iran could face increased pressure to withdraw from Iraq, thus depriving Tehran of its strategic depth in the Middle East. This scenario could accelerate negotiations for a new nuclear deal, potentially imposed by the Trump administration as early as January 20.

The losses suffered by Iran after the Israeli war and the fall of the Syrian regime, Tehran’s ally since 1980, cannot be underestimated. Now, Tehran faces two choices: either offer concessions and adapt to the new regional dynamics by opening up to the West, or accelerate its nuclear projects to gain deterrent power.

Both scenarios involve high costs: making concessions would mean abandoning an advanced defense policy practiced for 30 years, while a nuclear arms race would lead to increased international isolation, additional sanctions, and the risk of a joint Israeli-American military strike.

Thus, Iraq remains the center of attention, potentially representing the next battlefield in the strategic standoff between Washington and Tehran.