Do Bill Cosby's Recently Disclosed Admissions Make It More Likely That He'll Be Prosecuted?

FILE - In this Nov. 6, 2014 file photo, entertainer Bill Cosby pauses during a news conference. Cosby admitted in a 2005 depo
FILE - In this Nov. 6, 2014 file photo, entertainer Bill Cosby pauses during a news conference. Cosby admitted in a 2005 deposition that he obtained Quaaludes with the intent of using them to have sex with young women. In court documents released Monday, July 6, 2015, he admitted giving the sedative to at least one woman. (AP Photo/Evan Vucci, File)

On Monday, it was revealed that Bill Cosby admitted back in 2005 to having obtained Quaaludes to give to prospective sexual partners. This bombshell has understandably been seized upon by Cosby's accusers and others to support the accusations that have been proliferating in recent months. Do the new revelations affect the likelihood that Cosby will face criminal charges?

That's a complicated question, and the answer depends on the intricacies of individual states' laws. The first and most obvious issue is whether any potential charges are still prosecutable, or whether they're all "time-barred" by the applicable statutes of limitations.

The alleged incidents took place over several decades in a number of different states, so the first task would be finding out what each state's limitations period is for the type of conduct at issue. These periods are quite long in some states, and some cases unlimited. New York, for example, has no statute of limitations for first-degree rape, which includes sexual intercourse with someone who is "incapable of consent by reason of being physically helpless."

However, even for states with long or unlimited limitations periods, there's a catch. Many of the legislative moves to lengthen or eliminate these periods took place in recent decades. The Supreme Court has held that it's a violation of the constitutional Ex Post Facto Clause to "revive" a charge whose limitations period has run. Going back to the New York example, the elimination of the limitations period for first-degree rape happened in 2006. Crimes that had "run" by that time couldn't constitutionally be prosecuted, but crimes that were still "live" at the time of the change could constitutionally be subjected to the new period.

To make things still more complicated, although a state extending or eliminating a limitations period constitutionally can make the change applicable to past crimes that aren't yet time-barred, it doesn't have to. Some states will make the new rules applicable only to crimes occurring after the date of the new legislation or some other date.

And... we're still not done. Figuring out whether the statutory period has run may not be as simple as counting how many years have passed since the alleged conduct. Some state statutes provide that in certain cases the "clock" starts running at some different point--for example, when an alleged victim who was a minor at the time turns 18, or when the offense is reported to the authorities. And some provide that that clock doesn't run at all during any time when the accused person is outside the state.

The net result is that for any alleged incident we may need to consider not only what the limitations period is now in the relevant state, but also what it was at the time the conduct allegedly took place, whether and when that period was changed, whether any such change was made applicable to past offenses, when the limitations clock started to run, and whether anything suspended it at any point.

For charges that may still be prosecutable, what effect might the recent disclosures have? Again, it's hard to say.

First, it's far from clear that Cosby's admission would be admissible in any case that could now be charged. The default rule, historically, has been that a prosecutor can't introduce a defendant's past similar conduct for "propensity" reasons--for example, by proving that a defendant robbed a bank once before, to support the argument that he probably did it this time too.

But there have always been a number of exceptions to the rule barring evidence of past conduct. If, for example, there's something about the past incident that shows a particular "signature" or "modus operandi" similar to that used in the present case, the prosecutor has generally been allowed to present the past incident and argue that the person who did it this time is probably the same one who committed the similar act the last time. Some jurisdictions have gone further and enacted more sweeping rules--for example, that in any case alleging sexual assault, evidence of prior sexual assaults by the defendant is generally admissible.

Would Cosby's admission be admissible under any of these theories? It's possible to imagine a court going either way. A judge might conclude that the admitted conduct wasn't unique enough to come in under a signature or modus operandi theory; similarly, Cosby may not have admitted enough to prove a prior "sexual assault" for purposes of that rule. But these are close questions, and it's not hard to envision a judge going in the other direction.

In short, it's difficult to make generalized statements as to how the recently disclosed admission might affect Cosby's risk of criminal prosecution. The answers to all of the relevant questions can depend heavily on intricate details of individual states' laws. Even within a given state, the issues can be complex enough to make it difficult to predict how the legal questions might be resolved. And all of these factors are taken into account when prosecutors with potentially "live" charges are deciding whether to go forward. We'll all just have to wait and see.