George Zimmerman may be a crazed, racist, Neighborhood Watch-empowered psycho, hell-bent on bringing his own brand of justice to bear on anyone who dares trespass the streets near his home. Or he may just be a regular guy, attacked and savagely beaten by Trayvon Martin until he finally was able to get off a single shot in self-defense.

But now, at least, a court of law will decide. And even in light of Florida’s “stand-your-ground” law, this is as it should be.

From a public perception standpoint, it is abundantly clear that only public pressure could have gotten us to this point at all. Before the media coverage, marches, and online petitions, the police department in Sanford, Florida, refused to arrest Zimmerman, citing the stand-your-ground law as a bar (which may not actually be an accurate reading of the law—an interesting analysis, from the Wall Street Journal, is here). It also appears that the Florida State Attorney with original jurisdiction over the case, Norm Wolfinger, had little stomach for prosecution. In fact, both may have been suffering from a bit of “stand-your-ground fatigue”—i.e., if the likelihood of successful prosecution is minimal, why bother even giving the case a close look?

In that regard, the events of the past week offer useful insight into just how affected public prosecutors are by public perception—and the way they react when confronted with cases that will inevitably play out as much in the court of public opinion as in a court of law. With criminal and civil law reaching into so many aspects of our business and personal lives, such knowledge is helpful for all lawyers and clients.

Prosecutors, of course, will maintain that they are never affected by any concerns outside of the facts of the case. Indeed, the special prosecutor in the Zimmerman case, Angela Corey, who was appointed after Wolfinger stepped aside, took great pains at her April 11 press conference about the indictment and arrest to say just that. The line goes like this: Prosecutors follow the facts, and only the facts. If the facts show a violation that will lead to a conviction, they will prosecute.

It’s rarely that simple.

For one thing, prosecutors are human beings. They live in the same messy world we all do. Intense media scrutiny, political bias, and concerns over reputation all play a role in how they view each case that comes their way—and, more importantly, how much attention they bring to each case. In addition, they’re usually hardcore political animals, elected or appointed because they know how to play the public perception game, and play it well.

Prosecutors and regulators have shown this time and time again, particularly in an age when every filing and exhibit is subject to intense public scrutiny. Consider, for example, the increasingly deft handling of media when indictments are announced. As famed criminal defense lawyer Ted Wells, co-chair of the litigation department at Paul, Weiss, Rifkind, Wharton & Garrison, put it in my 2009 book, In The Court of Public Opinion: “Twenty-five years ago, an indictment was a legal document. You read an indictment these days—that’s the prosecutor’s press release right there.”

Another example: in 2010 the U.S. Department of Justice opened an internal investigation into leaks by DOJ lawyers in the Galleon insider trading case. I’d argue that such leaks from prosecutors’ offices to key media outlets increasingly threaten to capsize the unbiased administration of justice by painting investigation targets as “guilty,” in an attempt to publicly extort a settlement before trial. Just think about how many times you have read “sources close to the investigation . . .” in news reports relating to a government investigation of a civil or criminal matter. A quick news database search reveals more than 300 separate instances of that exact phrase in just the last month.

In this modern media age, it is becoming clear that prosecutors and regulators are as adept at playing to the media and broader public audiences as even the flashiest plaintiffs lawyers.

This is not to say that there is something unethical, biased, or corrupt in the way the Zimmerman case was handled by the special prosecutor. Ms. Cody appears to have operated with the utmost professionalism, taking great pains at her press conference announcing the indictment to argue that Zimmerman has the right to a fair trial and should not be presumed guilty or otherwise tried in the media. Many prosecutors would not have extended such a courtesy (see Eliot Spitzer’s treatment of former AIG head Hank Greenberg). But there can be little argument that public pressure influenced the intensity with which Cody took on the assigned task—not to mention the fact that the case was assigned to her at all.

It comes down to prosecutorial discretion. The facts may not change, but the manner in which they are handled, investigated, and reviewed can vary significantly. So, too, the conclusions drawn from such facts. Media, the Internet, and public pressure don’t change the law, but they do make prosecutors, regulators—all parties to legal proceedings—behave and react in different ways.

As a prosecutor, you can decide to bring a case . . . or not. So, too, as a regulator. Even plaintiffs and defendants in civil cases make a cost-benefit analysis before every case they take—i.e., is this litigation worth it? Will my return on investment be there? And even more subtly: What level of attention, time, and resources should I apply to a particular case. What’s the priority? Will I adequately staff it, or throw my “B” team on it and hope for the best. Will I use the financial resources at my disposal to pursue every lead?

All lawyers and their clients need to understand this calculus when plotting litigation strategy. Whether your case is a sensational murder trial, a sexual harassment claim, an antirust case, or SEC investigation, if it’s of any consequence, there’s likely an audience. And if there’s an audience, you can be sure the prosecutors and regulators will be playing to it.

James F. Haggerty, an attorney and communications consultant, is CEO of PRCG/Strategic Communications and the author of In The Court of Public Opinion: Winning Strategies For Litigation Communications (American Bar Association Publishing, 2009). He also hosts a weekly In The Court Of Public Opinion radio show on the VoiceAmerica Business Network.