With the accusations against Bill Cosby in the news now, we are also again hearing calls to get rid of the statute of limitations for, in this case, sexual assault.

At Comic-Con a few years ago I heard about the child pornography case against comic book store owner Gordon Lee, and how the prosecution kept changing the charge. The story is ridiculous. A year and a half after Lee supposedly committed the a crime against one person, they dismissed the case and recharged him with committing it against a different person.

Gordon Lee had the CBLDF to assist. Imagine, though, that he were on his own, his life savings gone into collecting, finding, and organizing a legal defense and now being told that he needs to start over. And besides having exhausted his money, it is now a year and a half later. He now has to mount a defense against a year-and-half-old crime that, if he was innocent, he didn’t ever expect to have to defend against.

The problem with relaxing fairness towards accused is that it hurts accused who are innocent far more than those who are guilty. If a person is accused of having raped a woman ten years ago, and he is guilty of it, he’s also the kind of person willing to lie on the stand. And he almost certainly has friends who are willing to lie on the stand. If he’s innocent, he’s never considered needing an alibi for a random moment in time a decade past.

The same thing that makes it easier to prosecute such cases—that people no longer remember their alibis—also makes it easier to make up alibis. If the hypothetical true rapist manages to get two friends to swear to his being somewhere else, it is extremely unlikely that anyone can break that alibi. It’s true that those two friends were probably somewhere else, but so what? No one will be able to pinpoint that to the precise night.

Our innocent accused, however, is much less likely to convince his friends to create a fake alibi. First, he’s not as likely to even try; second, the kinds of friends he has are less likely to convincingly go along with it; and third, he doesn’t have the experience to make the kind of alibi that is not easily refuted.

Fake alibis—those made with tickets or other paper—become more convincing over time. Ten years later, nobody is going to say the true criminal wasn’t at the concert that they have a ticket for. But the innocent person won’t have a ticket, because they never planned on needing an alibi that night. They never went to any concert, and they didn’t keep their ticket even if they did.

In Ain’t Nobody’s Business If You Do, Peter McWilliams describes the process from the perspective of an innocently-accused victim within the statute of limitations:

You are asked about people, incidents, and things going back as far as seven years. You are asked to remember where you were, who you were with and what you were doing at a particular time, on a particular date. If you’re like most people, you don’t remember what you had for dinner two weeks ago, much less what you did two years go, but “not remembering” is treated as a clear indication of “withholding evidence,” “interfering with justice,” and being “uncooperative.” If you happen to remember something, anything, these comments will be carefully recorded, and, if you happen to remember something different later, it will be taken as a sign that “you truly don’t have an accurate memory of the situation,” that you “lied to the police,” and, therefore, must be guilty (as we knew all along).

Now imagine not seven years, but ten years, or twenty years. Or in the case of some of the Cosby accusations, over forty years ago. What were you doing on May 15, 1974? What corroborating evidence do you have to prove it?

How difficult would it be for prosecutors to choose someone whose opinion everybody dislikes, and charge them with a forty-year-old crime long after any witnesses for their defense are dead or have (if they tell the truth) little memory of what the accused was doing that exact night forty years ago?

The advent of super-science only makes this worse. All evidence can be fabricated, even DNA, but the more of a scientific veneer the evidence has, the harder it is to dispute to a jury. And, of course, if the evidence was fabricated years ago, it becomes that much harder for the accused to show this.

I would hate to be charged with a crime that happened even five years ago. I have no record of what I did week by week, let alone day by day or hour by hour. There are even crimes for which there is no statute of limitations. That’s wrong. Our system is designed to ensure that the innocent are not wrongly accused and are not wrongly convicted. But delays of decades between the act and the charge give vindictive prosecutors or law enforcement far too much power. They help convict the innocent as much as the guilty.