The year 2017 was a year of sexual abuse and harassment allegations.

Many prominent men, including Harvey Weinstein, Dustin Hoffman and Matt Lauer, among others, have been accused of a broad spectrum of misconduct, from inappropriate behavior in the workplace, to physically groping victims' intimate parts. Forcibly touching another person without consent for sexual gratification is usually both a crime and a civil wrong.

Yet, many of these allegations that emerged in the last few months will never see a civil or criminal courtroom. This is because they happened too long ago and are outside the statute of limitations. The appropriately acronym-ed "SOL" is a set period of time, which varies drastically depending on the nature of the offense and the state in which it occurred.

The rationale behind an SOL is to afford protection to a defendant against stale claims after a significant period of time has elapsed, during which a diligent person would have accused the defendant.

With the passage of time, memories fade and witnesses may move, vanish or die. Scientific studies confirm that the passage of time erodes or even rewrites witness memory.

At the same time, statutes of limitations exact a toll on justice. They are, by definition, completely arbitrary. They make no distinction between just and unjust claims. They are also completely inconsistent from state to state and federal law.

Even a single allegation of groping invokes a confounding array of potential statutes. The civil SOL and the criminal SOL are not necessarily the same period of time, permitting a criminal prosecution where a civil lawsuit is foreclosed, and vice versa.

Many state legislatures have amended their statutes in cases of sexual misconduct to "toll" — essentially "stop the clock" on — the running of the SOL until the victim remembers previously repressed memories.

Another modern trend is to remove any time limit on the prosecution of rape and similar crimes. Public sentiment appears to be moving toward eliminating any time limitation on victims of sexual misconduct bringing claims or prosecuting defendants for sexual misconduct.

There is precedent for this.

The vast majority of crimes have limitations periods, which are a set number of years. As a general rule of thumb, the less serious the conduct, the shorter the limitations period. They vary from state to state, but a typical limitations period for misdemeanors might be two years. The more serious the crime, the longer the limitations period.

In our legal system, only the most heinous crimes justify no limitations period at all. The most notable example has always been murder.

Legislatures are heading in the direction of expanding or removing statutes of limitations for lawsuits or criminal prosecutions arising from sexual misconduct. When legislatures do away with limitations period, it sends a very clear message: For the worst of our crimes, a significant passage of time may result in an unfair prosecution or wrongful conviction. But, sometimes, society requires a conviction, at any cost.

Danny Cevallos is an MSNBC legal analyst. Follow @CevallosLaw