Granting immunity in order to get Mike Flynn’s testimony in congressional hearings would be a very bad idea, if history is any indication.

This NY Times story published in July 1990 explains what happened in the case of Oliver North, the former Marine who was a central character in the Iran-contra scandal during the administration of President Ronald Reagan (“NORTH CONVICTION REVERSED IN PART; REVIEW IS ORDERED“).

An appeals court threw out North’s convictions because the trial court had not properly determined whether evidence presented at trial had been improperly tainted by North’s testimony before Congress.

The bottom line is that testimony under a grant of immunity is likely to undermine criminal prosecutions, not only of the person granted immunity, but potential all of those accused of being involved in the same matters.

According to the 1990 story:

In the summer of 1987, Congress granted immunity to Administration figures like Mr. North and Mr. Poindexter over the reservations of the independent prosecutor, Lawrence M. Walsh. Congress moved quickly to get to the bottom of the affair, in which the Reagan Administration sold arms to Iran and diverted some proceeds to the Nicaraguan rebels.

Prosecutors Assess Ruling

Republican defenders of the Reagan Administration have said the urgency to get the hearings under way quickly stemmed from a politically motivated effort by Democrats to use the Congressional inquiry to criticize Mr. Reagan’s Iran-contra policies and to appear vigorous in investigating a high-profile scandal that aroused an outpouring of public concern.

The decision today demonstrates the difficulties in bringing to trial an official who has previously been forced to testify before Congress. [News analysis, page 7.]

Here’s a section from the decision of the U.S. Court of Appeals for the D.C. Circuit.

When the government proceeds to prosecute a previously immunized witness, it has “the heavy burden of proving that all of the evidence it proposes to use was derived from legitimate independent sources.” Kastigar, 406 U.S. at 461-62, 92 S. Ct. at 1665. The Court characterized the government’s affirmative burden as “heavy.” Most courts following Kastigar have imposed a “preponderance of the evidence” evidentiary burden on the government. See White Collar Crime: Fifth Survey of Law-Immunity, 26 Am.Crim.L.Rev. 1169, 1179 & n. 62 (1989) (hereafter “Immunity”). The Court analogized the statutory restrictions on use immunity to restrictions on the use of coerced confessions, which are inadmissible as evidence but which do not prohibit prosecution. Kastigar, 406 U.S. at 461, 92 S. Ct. at 1665. The Court pointed out, however, that the “use immunity” defendant may “be in a stronger position at trial” than the “coerced confession” defendant because of the different allocations of burden of proof. Id.

There’s a much longer explanation of constitutional basis of the issue. Worth at least skimming.

It seems that the Trump administration might back immunity as a way to make future criminal prosecutions difficult, if not impossible. That’s not a good deal for the rest of us.