There are only two people who know exactly what happened on the night of Feb. 26 in Sanford, Fla., and one of them is dead.

Angela Corey, the Florida special prosecutor investigating the fatal shooting of Trayvon Martin by George Zimmerman, announced this afternoon that she intends to prosecute Zimmerman for second-degree murder. Because Martin is unquestionably dead, and because Zimmerman indisputably caused his death, the single proposition the prosecution must establish is that the killing was unlawful.

But there is almost no chance the state will be able to obtain a conviction, and despite Corey’s assertion that public pressure did not influence the decision to move forward with the prosecution, the fact that Florida authorities did nothing for six weeks after the killing makes her claim implausible. The decision to prosecute therefore seems more intended to assuage the community’s moral outrage than redress a legal violation.

The problem here is that there are actually two problems: one is what George Zimmerman did, which was to shoot and kill an unarmed young man who had every right to be where he was. The second is that Florida law allows that to happen.

Chapter 776.013(3) of Florida law—the now-infamous “Stand Your Ground” provision—states: “A person who is not engaged in an unlawful activity and who is attacked in any other place where he or she has a right to be has no duty to retreat and has the right to stand his or her ground and meet force with force, including deadly force if he or she reasonably believes it is necessary to do so to prevent death or great bodily harm to himself or herself or another or to prevent the commission of a forcible felony.”

The so-called Castle Doctrine—named after the quaint British expression that a man’s house is his castle—dates back at least to the early 17th century and permits someone in his or her home to use lethal force against an intruder. American colonists brought it with them, and today, more than half the states have versions of the doctrine. The effect of the Castle Doctrine is to override the duty to retreat. So even if it is perfectly possible for the homeowner to safely escape, the Castle Doctrine means the homeowner does not have to.

Many states have adopted bulked-up versions of the doctrine and done away with the duty to retreat in places besides the home. Others have done away with the duty altogether, so long as the person believes lethal force is reasonably required to protect himself or herself from serious injury.

But Florida law remains unique. Unlike Texas law, for example, which does not permit deadly force to be used by someone who provokes hostile action, Florida allows someone to use deadly force even if his conduct somehow created the very threat to which his lethal force responds. So if, as Zimmerman claims, Martin walked toward him and asked why he was following him, and Zimmerman reasonably felt threatened by that question, Florida gives him permission to shoot, even though his very conduct provoked Martin’s question.

That’s not the end of it: Florida law also permits the use of lethal force by someone whose own welfare is not directly threatened. It even permits the use of lethal force where the only threat is to property—including property not owned by the person using the force.

In Florida, therefore, the Castle Doctrine extends across every inch of the state, and it allows someone to kill somebody else even if that other person is not threatening any human being. In fact, Florida’s law imposes but a single requirement regulating its use: The person who uses lethal force must be acting on the basis of a “reasonable” belief.

It is precisely the statute’s use of the word “reasonable” that makes it possible for Corey to pursue criminal charges against Zimmerman. If his action was unreasonable, then the killing was unlawful, and he is guilty of second-degree murder.

The prosecution’s case will therefore be built entirely around the reasonableness of Zimmerman’s conduct. The problem for the state is that it bears the burden of proof, meaning it will essentially be required to prove that his belief was unreasonable. Since the principal witness who could help establish that fact is dead, the probability of a conviction seems exceedingly remote.

There will presumably be witnesses who will testify as to their perception of what was happening. Trayvon Martin’s girlfriend might testify about her conversation with him. Other eyewitnesses might say that they saw Zimmerman acting aggressively. Others still might report on whether Zimmerman had physical wounds.

This editorial originally appeared on The Daily Beast. Read the rest of the editorial here.