How often does invoking silence make a decisive difference for a defendant?

AIUI, generally, the cops or feds don’t arrest someone unless there is probable cause. And in the case of the feds, they are particularly meticulous and usually assemble massive amounts of evidence.

As such, does invoking the right to silence usually really make a real difference? A confession after being Mirandized is, of course, pounding the final nail into your own coffin, but if you’re already arrested don’t the authorities usually have enough evidence to get you convicted anyway even if you invoke silence?

In other words, in what percentage of cases does silence vs. talking make the true difference between walking free and being convicted? 20%?

So, the trial is just a formality?

I doubt there is any way to know. Some people do talk and are acquitted. Some convicted. Many don’t and are convicted. There are certainly cases where a defendant’s only chance is to take the stand and explain something, but those are rare. Self defense, for example, or consent in a rape case.

The vast majority of defendants plead guilty rather than go to trial.

The times we can be sure it has made a difference is when an arrestee invokes the right to remain silent, the police fail to respond appropriately and discover important evidence based on the elicited statements.

People are convicted on the basis of such evidence and then wind up going free after an appeal.

On the other hand, such statements get suppressed sometimes, and then the person still gets convicted.

It depends on how strong the case was without the statements, as you recognize.

“Probable cause” is a much lower bar than “beyond any reasonable doubt”.

Also, many arrests never lead to an indictment. True, most indictments do lead to some sort of conviction, but it is not uncommon for the DA to not bring charges or the police to drop charges. Sometimes the arrest is made on fairly flimsy PC, in the hope you will confess.

Unless your lawyer advises you to do so, staying silent never hurts. Speaking will get you in trouble.

STFU and get a lawyer.

There are also a wide variety of other possible interactions with police, short of an arrest. Maybe they don’t arrest until they have a lot of evidence… but not so for just “Hey, could we ask you a few questions?”, or a traffic stop, or whatever. And whatever you say in one of those interactions might be the evidence they end up using to later arrest you.

Isn’t this usually a state vs fed thing, though? IIRC, the states often trawl about loosely and do things sort of sloppily but the feds usually evidence-stalk someone for so long that their goose is fully cooked by the time they are arrested.

True. But just to clarify,

Cops need reasonable articulable suspicion (RAS) to detain you. They need probable cause to arrest you.

Depends what, in my (IANAL) opinion. If it’s murder or kidnapping, and they have evidence - they will keep digging and if they find anything, they will find enough to convict you - and certainly threaten dire consequences if you don’t cave and plead guilty. Serious crimes probably get serious attention.

OTOH, if it was an altercation with a neighbour, and “was it you who broke their car window?” and you say nothing, odds are unless there’s video evidence or an independent eyewitness, they will chalk it up to “unclear what happened” unless they can get a confession or some stupid talk from the perp.

I always wonder about these cop shows where they have several days and a lot of travel time to investigate a break-in or a mugging or a car theft. How many incidents do a pair of detectives have on the go at any one time, let alone a pair of patrol cops? If nobody lays out reasonable evidence during the first round of interviews, how many times will they be back?

But at the same time, if the crime is serious enough, the penalty will be severe enough that the defendant has little motive to talk.

Remaining silent when being questioned about murder - if you’re convicted, you still face life imprisonment or death.

Confessing and pleading guilty when questioned about murder - you get life imprisonment or death.

Not quite what the OP is asking but there are many innocent people convicted solely on their (false) confession or other information they gave the police. You were with the defendant at 11pm? Looks like the coroner “corrected” the time of death from 3am to 11pm.

If they had been silent it probably would have been decisive.

As @Proscrustus says, there is no way to know definitively. However, “beyond a reasonable doubt” is a high standard. Obtaining convictions is hard. The prosecution has to prove every single element of the crime BRD. The minute a suspect opens their mouth they are almost certainly admitting various elements of the offence or facts that assist with proving various elements of the offence. It would be highly unlikely that invoking the right to silence did not regularly make a decisive difference.

As to the idea that some LEO may have built a watertight case against the suspect before they arrest - maybe, but very often they will have taken their investigations as far as they can and are fairly sure of their case, but are maybe missing a few key pieces in the puzzle. Do they drop the case or arrest and try to get the suspect to make admissions? The latter. So, again, it is highly unlikely that invoking the right to slience did not regularly make a decisive difference.

This isn’t relevant. The question is how often invoking silence makes a definitive difference. That is not the same question as how often an accused caves in and pleads.

While confessing of your own volition is unlikely to make much difference in your sentence, absolutely a defense attorney can negotiate a reduced sentence or a plea bargain to a lesser count in a murder investigation – and he or she will be in a stronger position to do so if you’ve kept your mouth shut. Talking to the police is opening the negotiation by just giving something valuable away.

Well if it’s the feds just talking alone is enough to send you to prison, if they can show you knowingly told them a false statement (see Martha Stewart). Though AFAIK this is generally happens in cases where they don’t have enough evidence to arrest you for the original crime, but do have enough to show your statements were false.

You can’t talk your way out of trouble, but you can talk your way into it. So, there’s no benefit to talking but there could be significant downside. If they’ve got you on something or decent odds against you, no reason to make it worse.

In countries like the US where plea bargaining is a defining character of the judicial system, sure. In other jurisdictions it’s uncommon, or even illegal, so there the proportion of defendants pleading guilty before trial is far lower. In the UK it’s currently 54%.

My point was the accused may cave under pressure and talk “look, we have all this, it will go easier if you confess.” No it won’t, it just makes things go easier for the prosecutor. Anyhoo, the main point is - if it’s a major crime, the police will dig deep and your silence may have less effect. For minor crimes, the police probably don’t do much more than a minor superficial investigation and taking statements. Thinking you’re smart enough to talk your way out is quick way to talk yourself in deeper.

I saw a description once where it was mentioned the British system is simple - the prosecution can offer 2/3 of what they will ask for at trial. This is low enough that innocent people will take a chance at trial, while enough that someone who knows they’re going to jail will take the lesser plea.

Not to be confused with Aaron Schwarz’s offer in Boston - 35 years if you go to trial, or 6 months if you plead guilty. (He chose the third option - suicide.) Or the reason Michael Cohen pled guilty - “If you don’t, we’ll also charge your wife and drag her into court, even though we know she’s totally innocent and had no idea what you were doing.”