“No boots on the ground” has evolved into over 6,000 US troops in Iraq, and pledges that they would play no combat role in the war against ISIS has now given way to US ground troops being deployed on the front lines in Iraq’s largest invasion to date, the ongoing attack on the massive city of Mosul.

The troops are special forces who are being used as “forward air controllers,” and are meant primarily to do targeting for US warplanes that are constantly pounding the city from above. Officially, these troops are still being classified as “non-combat.”

Pentagon officials later insisted that “most” of the troops in Iraq, which again is over 6,000 of them, aren’t on the front lines in Mosul. The ones that are, however, seem like they’ll inevitably end up participating in combat, whether they’re classified that way or not.

The US has been struggling with this classification of troops problem throughout the ISIS war, with Pentagon officials occasionally admitting that troops are engaged in combat in Iraq, but the administration overwhelmingly arguing that they’re not technically in combat roles.

This pretense is always harder to maintain when there are casualties, and despite the Pentagon insisting that officially, nothing has changed with the invasion of Mosul, the indications are that a much larger number of US troops are in front line roles in Mosul than anywhere else in this conflict.

Pentagon officials indicated that the number of troops involved in the air controller position was in the 100-200 range, while an unknown number of others, classified as advisers, remain in the area just behind the front lines.

It’s a virtual given that US forces will be targeted by ISIS forces as the fighting picks up, and this includes those on the bases just behind the front lines. Already, ISIS fired a makeshift chemical weapon at the Qayara base, which is housing large numbers of US troops. Pentagon officials have said more chemical attacks are to be expected.

While in previous instances of US troops in combat in the ISIS conflict have centered on the Obama Administration’s interest in downplaying the risk of American casualties, in this case they also seem very interested in selling the idea that this is an “all Iraqi” operation, and that the US troops are just sort of along for the ride. The hope seems to be that a victory here would give the Iraqi army some credibility which it has lacked throughout the ISIS war, though it might also allow the US to avoid blame if the battle doesn’t go to plan.