I think you're being obtuse on purpose.
Probable cause is not a high standard especially when the government can present it's case with no opposition. That is why the old adage of being able to indict an inanimate object is both scary and true.
You think that I am being obtuse on purpose? I regret that you feel that way. However, it is apparent to me that you are a bit confused on the function and purpose of a Grand Jury and what determines probable cause. I am not debating the fairness of a Grand Jury, but rather describing it's purpose in our justice system.
Here is my understanding of probable cause after over 20 years of experience in law enforcement at the local, state and federal levels.
Probable Cause is when a reasonable person that is presented with the facts and circumstances regarding the alleged crime would conclude that it's
more probable than not that a crime has been committed by the accused.
It is a strict legal standard that must be met before any arrest, search or seizure can occur. This is a requirement based upon the U.S. Constitution so all levels of law enforcement must adhere to this standard.
For the Grand Jury to indict they must conclude that probable causes exist that a crime was committed and who committed it. The Grand Jury is made up of common citizens who are considered to be reasonable. It does not consist of attorneys, prosecutors, or LEO's or Judges. There is a foreman who is appointed to lead them.
A law enforcement officer (LEO) can arrest someone without a warrant based solely upon probable cause. This is called a warrantless arrest and there is nothing a defense attorney can do to prevent this from happening, it's a fundamental concept of our justice system.
The arrest just like any Grand Jury indictment does NOT determine guilt, but rather that based on the facts and circumstances it is more probable than not that a crime has been committed by the person who was arrested.
However, most prosecutors prefer that a LEO not make a warrantless arrest and procede cautiously especially in high profile cases. Therefore, the prosecutor takes the case to a Grand Jury where it's the prosecutor's responsibility to present the facts and circumstances to the Grand Jury including any exculpatory evidence that may serve to exhonorate the defendant.
It is not intended to be a confrontational hearing but simply a fact finding event to determine probable cause. If the allegations are confirmed by the Grand Jury then the Forman returns a true bill for the indictment. Once the defendant is indicted for the crime an arrest warrant is issued and the defendant goes to jail where he is usually given a bond, and is released from jail while he awaits trial because he is still presumed to be innocent until guilt is proven or accepted by pleading guilty.
At this point, in the process the defendant is appointed or hires legal counsel if he doesn't already have one to prepare a defense. The vast majority of all defendants usually realize that thier best option is to eventually plea to something, and they usually do. However, some maintain thier innocence and go to trial.
As for your comments regarding the ability of a prosecutor to indict anything, in my experience, the Grand Jury is simply a formality because at this point the prosecution has enough evidence that in his opinion he can prove the case beyond any reasonable doubt that the accused is guilty and is willing to go to trial. So with that in mind the Grand Jury IS viewed by many to be just a rubber stamp because there is an abundance of evidence to determine probable cause.
I hope this helps.