Firstly, if a person asserts their Fifth Amendment right not to testify on the basis that their testiimony "MIGHT" incriminate them, they are usally not an attorney, and therefore not an expert at law, so it is up to the prosecuter, or other authority who is doing the questioning, to PROVE that their testimony will not be incriminating. For instance, suppose "Person A" is arrested while committing a burglary. "Person A" asserts in court that it couldn't be him because he was with "Person B" all nite at his home. But "Person B" gave a key to "Person A" to committ the burglary, and the police and prosecuters do not know that fact. How can the prosecuter or judge say: "You MUST testify," when "Person B" KNOWS his testimony could implicate him because of a fact the police and prosecuters know nothing about ?<quoted text>PLEASE explain how giving testimony that implicates other criminals is self incrimination.
Secondly, like it or not, every individual posesses a "Miranda Right" to keep silent when question by the police or other government authorities, be they from the FBI, IRS, DEA, Coast Guard, or WHATEVER governmental autority they are from.
You CAN'T be compelled to answer questions asked of you by an agent of teh government, nor can you be compelled to talk to them at all.