Can the Fifth Amendment protection against self-incrimination be invoked in a civil deposition? Can the Fifth Amendment protection against self-incrimination be invoked in a civil deposition? Assuming it can be, what potential consequences may the invocation have, if any?
If the question asks, "did you do X" where X is or includes a crime that you could be criminally prosecuted for, you can invoke the 5th amendment in refusing to answer that. I have seen that done and seen that objection to the question sustained in court. However, if admitting to X would provide only civil liability, then the 5th would not apply. At trial, you may also have to take care not to give direct testimony on things that are so closely related that you "open the door" to being required to answer that question. For example, you can't say "I don't owe because I did X" and then expect to not have to answer "So just to be clear, did you do X?" Also, depending on context, invoking the 5th might cause a jury to view your testimony more skeptically (cpast points out that "For civil cases, adverse inferences based on pleading the fifth are totally okay"), and if that's going to come up you should ask your attorney about whether or not it'd be a good idea strategically.
The Fifth Amendment would not apply, because nothing in the testimony would incriminate the doctor. Indeed nothing would be at all likely to incriminate the President either, it is not a crime to be unable to carry out Presidential duties. It is likely in such a case that the President would waive confidentiality. In that case the doctor could testify freely. If the President insisted on confidentiality, and attempted to prevent the doctor from testifying to Congress, there would be a conflict between the power of Congress to compel testimony, in this case on what is clearly a vital national issue within the scope of the needs of Congress, and traditional doctor-patient confidentiality, let alone the requirements of HIPAA. I am not sure how this conflict would be resolved. There might be an emergency application to the Supreme Court, but the SC does not usually do very well with truly urgent issues. The Pentagon Papers case and Bush V. Gore indicate some of the problems that can arise. If the doctor was prevented from testifying, that might incline members of congress to think the testimony would not be favorable to the President, and thus tend to suggest that they should not approve the President resuming or continuing his or her powers and duties. But that is rather speculative. The 25th has never been invoked, and the detailed procedure that would be followed if it were is not very clear. I am not aware of any similar situation in which medical testimony has been demanded to deal with an urgent issue, but the patient has attempted to block it. I think this case must be considered to be undecided until it actually arises and a court rules.
I have not found a case directly on point, but there is a case in the right neighborhood. In Flordia v. Carter 364 So. 2d 1249, Carter was charged with perjury for making a false statement under oath. He recanted his testimony in a letter to the defense attorney the next day. Subsequently he was charged with perjury: the trial judge dismissed the case based on his having recanted (which is a defense to perjury). The judge said (quoted in the appeal below and citing a relevant precedent Brannen v. Florida 114 So. 429) It matters not whether Carter knew his original testimony was false or whether he was merely mistaken. "The law encourages the correction of erroneous and even intentionally false statements on the part of a witness, and perjury will not be predicated upon such statements when the witness, before the submission of the case, fully corrects his testimony." The lower appeals court rejected the trial court's dismissal, saying Recantation is a defense to an allegation of perjury only where there is an acknowledgement of the falsity of the original sworn statement, a voluntary retraction of that statement, and a new statement which discloses the true facts. It is not a viable defense where the perjured testimony has substantially affected the proceeding or it has become manifest that such falsity has been or will be exposed. Otherwise, one could rest on his lie, allowing it to substantially affect a proceeding, and never retract unless the falsity had been exposed. This would provide no inducement or encouragement to tell the truth. That court basically felt it was based on the threat of being discovered, and felt that a particular state statute had taken away the recantation defense, so they reinstated the charge. The appeal to the Florida Supreme Court, Carter v. Florida 384 So. 2d 1255 basically declared that the appeals court was wrong about the statute (they officially held that recantation is a defense to perjury). They concluded that Carter gained nothing by recanting (that was a distinguishing feature in a precedent that the lower court favored). The dissent in this decision opined that It may be that the false deposition testimony by Dr. Carter was inadvertent and without criminal intent.... These, however, are factual issues and should be resolved by a jury rather than by the trial court on a motion to dismiss. What unifies all opinions on the matter is that a false statement made under oath must be recanted. The reason why Carter was not convicted was that he (possibly) was unaware that his testimony was false and he did recant when he became aware of the facts.
In the united-states, attorneys are almost never placed under oath. Their statements -- whether they are assertions of fact or legal arguments -- are not evidence, and they are not subject to cross examination. There are limited circumstances in which an attorney would be competent to present actual evidence. In such cases, the attorney would be sworn in as a witness and subject to cross examination, but the attorney would likely also be disqualified from acting as an attorney in such a situation under Model Rule 3.7.
The burden of proof is always on the plaintiff (except for counterclaims brought by the defendant against the plaintiff). In your example, the businessman has to prove that he did not rape her.
To answer the first question, the answer seems to be "generally not." In federal courts, this is explicitly not allowed -- rule 6(d) of the Federal Rules of Criminal Procedure states that the only people who can be present before a grand jury are government lawyers, the witness being questioned, interpreters, and a court reporter In state courts, the rules vary by state. However, again, private citizens are generally either completely not allowed to act as prosecutors, or are only allowed to act as prosecutors in a restricted set of situations and subject to the ultimate control of public prosecutors. For instance, in Virginia (which allows private prosecutors), the private prosecutor can't speak in front of a grand jury, initiate a criminal case, or participate in a decision to dismiss charges (page 23). In New Hampshire, private prosecution is limited to misdemeanors with no possibility of jail time, and again the state can dismiss charges (page 8). Rhode Island, like New Hampshire, allows private prosecution for misdemeanors but lets the state dismiss charges (page 11). The justification for allowing the state to dismiss charges is generally "prosecution is inherently a governmental task, so the government must retain ultimate control."
The defense lawyer has the duty to do the best for his client. The client will be convicted if he or she is guilty beyond reasonable doubt. If the lawyer can create a reasonable doubt and manages to free his client then he has done a good job. So yes, if the lawyer knows that some other person might have committed the crime, to the degree that it creates reasonable doubt, then the lawyer must raise this. Of course if it turns out that there is just some phantasist making wild accusations, that might not be helpful.
There's an interesting philosophical debate you can have. By the plain text of the First Amendment, it protects libel. Aside: Yes, the First Amendment does apply to libel cases. A libel case, like all lawsuits, involves the government's judicial branch using its coercive power to make you pay money as a result of your speech, based on a law requiring you to pay money for certain kinds of speech. Tort law is not optional; a libel case isn't "you promised not to say bad things and then said bad things," it's the government saying "what you did is bad, now pay the person you hurt because of your speech." The idea that "you can say it, you just have to face the consequences" isn't enough and hasn't been for quite a while now. Traditionally, the main point of freedom of speech was that a court couldn't stop you from saying something, but could only seek to punish you after the fact (and for that you get a jury, a public hearing, etc.) But more recently, courts realized that subsequent punishment had similar effects to prior restraint. If you're going to be punished for some kind of speech, you're going to steer clear of saying anything a jury might think is that kind of speech. Libel law is heavily influenced by the First Amendment, and has been for over 40 years. The First Amendment looks like it protects libel, but it also looks like it should protect your right to reprint any book you want. It also looks like it should protect your right to tell someone "go and murder this person." It also looks like it should protect your right to say whatever you want in court, whether or not it's true. It also looks like it should protect your right to falsely shout "fire" in a crowded hall, with the intent to cause a stampede (this isn't just a turn of phrase, there was an actual incident in which 73 people were killed which is believed to have started when someone falsely shouted that there was a fire). It also looks like it should protect your right to post a sign saying "There is a bomb at this elementary school." Yet the Constitution explicitly sanctions copyright, and no one would seriously conclude that Congress may not protect the integrity of the judicial process by punishing perjury. Ordering a hit, making bomb threats, intentionally causing panics -- the fact that speech is a key part of these can't mean that the government isn't allowed to criminalize them. You cannot run a civilized society in which death threats are legal. So, the courts interpret. Language in the Constitution that appears absolute is understood to have implied exceptions. The people writing the document were well aware that perjury was generally a crime. The same Congress that proposed the First Amendment passed a law criminalizing perjury. Sure, you're punishing someone based on their speech, but it's clearly not meant to be protected. You can't run a court system without perjury laws, and its absence from the First Amendment doesn't mean that the First Amendment thereby upended this basic principle. The courts have identified a number of kinds of speech that, by longstanding practice, are not protected. Intellectual property violations are one. Obscenity is another. So are threats. So is "speech integral to criminal conduct" (e.g. "what'll it be, your money or your life?") And so is defamation. The text of the First Amendment may not exclude it, but courts have uniformly held that it's not something the amendment was ever meant to protect. The First Amendment does still pose constraints, which are some of the most defendant-friendly in the world (interestingly enough, US law is descended from English law, and English libel law used to be among the most plaintiff-friendly in the world). It's not libel if it's true. It's not libel if it's an opinion (unless it's a statement of fact dressed up as opinion). It's not libel unless you were at least negligent; if it was about a public figure, you have to have known it was false or seriously doubted its truth. But these restrictions leave a core of speech that is and always has been punishable.