An initial caveat for those that wish to brand me a Clinton apologist (which I am not): I have no idea whether the allegations allegedly made by Lewinsky are true. That being said, let me explain how the truth of the allegations may become irrelevant.

Lets start with what charges Lewinsky could lodge against the president in an open forum and with the support of special counsel Kenneth Starr. She could say (1) I had a sexual relationship with the President, and (2) the President asked me to lie in a deposition I was compelled to give in the civil lawsuit filed against Clinton by Paula Jones.

With these being the allegations, how would the Clinton lawyers seek to discredit Lewinsky? It isn't very difficult.

First of all, she doesn't even get out of the starting blocks before being branded a liar. Make that an admitted liar. Either she did not tell the truth in an affidavit when she said she did not have sex with the President or she did not tell the truth when the opposite was stated in a secretly taped conversation by Linda Tripp. For Starr, the worst case scenario exists in that he needs the allegation about the sexual relationship to be true. (If they are not true, obviously, Clinton did not tell her to lie about their existence). With that being said, Starr must subscribe to the proposition that  his star witness has lied under oath in the affidavit. If an oath meant nothing when she signed her name, the Clinton lawyers will argue, how are we to believe it means anything to her the next time she swears to tell the truth.

But the problems for Starr do not end there. Apparently Lewinsky wants immunity from prosecution for being the aforementioned liar under oath. If this immunity is granted, then (and only then) will she freely testify. What a dilemma for Starr: Your star witness is a liar, but she will not "tell the truth" unless she is promised that she will not be prosecuted.

The granting of immunity can cripple even the most truthful witness because the implication is clear: the witness is saying whatever the government wants her to say simply to save her own neck. Such a scenario is trouble for a testifying witness who has been granted immunity for even run of the mill crimes. For example, one can infer that a drug dealer who has been granted immunity may also use drugs. However, the crime of drug use or drug dealing does not necessarily mean that he has a predisposition to lie.  Lewinsky, on the other hand, will have been granted immunity for the worst crime in the eyes of a jury which has been called upon to pass upon her truthfulness: the offense of being untruthful.

For these reasons, Lewinsky's cross examination would be brutal. And this is true even if the foregoing is the only baggage that Lewinsky brings to the witness stand. What if, however, additional evidence comes forth that calls into question her credibility even more? Certainly she will be offered book or movie deals, so the more elaborate her story, the more lucrative her position. This is fertile ground for Clinton's attorneys. Furthermore, what if there are other incidents of untruthfulness in her background. At the time of this writing, there is already at least one allegation that she engaged in a serious falsehood while in college.

Lewinsky may very well be telling the truth. Who knows. But regardless of the truthfulness of the allegations, our criminal justice system is first and foremost based upon what can be proven.   If her allegations are credible, it is unfortunate that her very own words will never be the sole basis to establish their existence.

Barry Green is the District Attorney for the 271st Judicial District.