Donald Trump inherits Obama's mess: U.S. troops in Iraq are advancing on ISIS-held Mosul

In a phrase that defies logic, Reuters reports that American ground troops are preparing to advance to the front lines in Mosul in a new phase of a two-month-old battle for the city, the largest combat role for American troops in Iraq since they "fulfilled President Barack Obama's pledge to withdraw from Iraq in 2011."

Mosul is an Islamic State stronghold, and the push to retake it is used as rationale for keeping as many as 5,000 (and growing) American ground troops there, fighting alongside 100,000 Iraqi troops — as well as members of the Kurdish security forces and Shi'ite militiamen. Elite Iraqi soldiers, backed by U.S. advisers and an international coalition providing air strikes and training for ground troops, have already retaken a quarter of the city. The next phase will be conducted by an elite Iraqi Interior Ministry strike force and, if successful, will put American troops inside the city proper and at much greater risk. The risks, given the rewards, are calculated as worth the trouble.

From Reuters:

Mosul, the largest city held by Islamic State anywhere across its once vast territorial holdings in Iraq and neighboring Syria, has been held by the group since its fighters drove the U.S.-trained army out in June 2014.

Its fall would probably end Islamic State's ambition to rule over millions of people in a self-styled caliphate, but the fighters could still mount a traditional insurgency in Iraq, and plot or inspire attacks on the West.

However, there could be trouble for President-elect Donald Trump if Mosul falls before he's inaugurated in January.  According to one writer for Lifezette, who interviewed soldiers familiar with the fighting in the region, "The Iraqi Army and much of the militias who are doing the 'wet work' are Shiite Muslims. Iran has gained considerable influence in Iraq through their support of Shiite militias — now numbering an estimated 100,000 strong."

More troubling, there may be consequences for the U.S. fighting alongside troops heavily influenced by Iran in a region that has been notoriously fickle in its allegiances and willingness to wage war. Interviews with soldiers just back from the region warn of that growing Iranian influence as a potential powder keg of future conflict:

The increase of Iranian military involvement and influence in Iraq should also be a chief concern for the incoming administration. Information released by the Obama administration appears to deliberately leave out Iranian troop numbers, while readily providing precise numbers of ISIS fighters.

However, going back to March 2015, the Kurdish authority accused Iran of sending upward of 30,000 troops into the country to assist the Iraqi government in its fight. In August 2016, a senior U.S. defense official reported that there were approximately "100,000 Iranian-backed militia" in Iraq, under the command of the "Quds Force" — more generically known as Iranian Special Forces. This is the same Iranian organization that the U.S. military holds directly responsible for killing some 500 Americans during the Iraq War. While the real numbers aren't necessarily clear to the American public, they dwarf U.S. troop figures, which stand at some 5,000.

Another special operations source put it bluntly: "Look at who in the region has the presence of force: Is it us — or is it the Iranians?" His cynicism is not without merit.

With Turkey, which commands a military force just outside of Mosul, publicly claiming the U.S.-led coalition is supporting ISIS, Secretary of State John Kerry's speech Wednesday outlining his vision for peace in the Middle East will hopefully address the question of the vacuum that will be left if the U.S. and Iraqi troops are successful in ousting ISIS from Mosul and which regional power will fill it.