On July 2, 2012, First Lieutenant Clint Lorance led a patrol in Afghanistan. During that patrol, three men approached on a motorcycle. After warning shots were ignored, and the unarmed men kept approaching the patrol, Lorance ordered his men to fire on them. Two of the men were killed, and a third fled. The third man who fled was quickly captured, and a test performed in the field revealed he had explosive residue on his hands, as did the two men who were killed. Yet in 2013, Lorance was court-martialed and convicted of murder. The reason? Violating rules of engagement by opening fire on unarmed personnel. He currently is serving a 19-year prison term in Leavenworth while his case is on appeal.

With that controversial case in mind, some might be asking, what are rules of engagement? According to Army Doctrine Reference Publication 1-02, “Terms and Military Symbols,” rules of engagement are defined as, “Directives issued by competent military authority that delineate the circumstances and limitations under which United States forces will initiate and/or continue combat engagement with other forces encountered.” In short, these rules dictate when and how our troops can fight the enemy, and what our troops can target.

One pop culture example of rules of engagement can be found near the start of the 1986 movie “Top Gun,” where an American pilot being harassed by a Soviet MiG asks for permission to fire and is told not to fire unless fired upon. The “how” part is a little harder, but it usually involves telling the troops which weapons they can use. Troops could be told to only use precision-guided weapons such as Paveway laser-guided bombs or GPS-guided Joint Direct Attack Munitions to limit collateral damage.

That takes us to “what” our troops are allowed to target. Some targets are taken off the list — and rightly so — by international conventions. This includes hospitals, aircrew that have bailed out, and civilian targets. But other targets can be taken off the list for just about any reason by the commander in chief, secretary of defense, or other higher-ups.

For example, the Obama administration had long refused to allow air strikes on major oil production facilities controlled by the Islamic State. The reason for allowing ISIL the use of those facilities? They did not want to risk damage to the environment.

While some strikes on ISIL’s oil racket have since taken place, it’s only cut production by about 25%. That means the Islamic State still pockets nearly a million bucks a day, which it zealously spends on murder, mayhem and assorted propaganda. Blowing those refineries to little pieces would deny the Islamic State a big chunk of this change.

Now, let’s be clear: Bombing oil refineries comes with considerable environmental costs. But when ISIL is butchering civilians in Western cities, beheading Christians and journalists, throwing homosexuals off the top of buildings, burning prisoners alive and carrying out a huge trade in sex slaves, our concern about the local flora and fauna seems a bit overwrought. On a related note: At one point last year, 75% of our combat sorties came back still carrying their ordnance due to highly restrictive rules of engagement.

Ultimately, the tone for rules of engagement are set by the commander in chief and his secretary of defense — neither of whom seems to care that the targets we refuse to hit today merely guarantee a stronger and richer Islamic State tomorrow.