Because different substantive and procedural rules apply to civil and criminal contempts, distinctions between the two forms of contempt are important. "Criminal contempt is a crime in the ordinary sense," Bloom v. Illinois, 391 U.S. 194, 201 (1968), and "criminal penalties may not be imposed on someone who has not been afforded the protections that the Constitution requires of such criminal proceedings." Hicks v. Feiock, 485 U.S. 624, 632 (1988). These constitutional protections include the right (1) not to be subject to double jeopardy, see United States v. Dixon, 509 U.S. 688, 695 (1993); In re Bradley, 318 U.S. 50 (1943); (2) to receive notice of the charges, (3) to receive assistance of counsel; (4) to receive summary process; (5) to present a defense, Cooke v. United States, 267 U.S. 515, 537 (1925); (6) not to self-incriminate oneself, and (7) to proof beyond a reasonable doubt, Gompers v. Bucks Stove & Range Co., 221 U.S. 418, 444 (1911). For serious criminal contempts involving imprisonment of more than six months, these protections include the right to a jury trial. Bloom, 391 U.S. at 199.

By contrast, civil contempt sanctions--which are designed to compel future compliance with a court order--are coercive and avoidable through obedience, and "thus may be imposed in an ordinary civil proceeding upon notice and an opportunity to be heard. Neither a jury trial nor proof beyond a reasonable doubt is required." International Union, UMWA v. Bagwell, 512 U.S. 821, 114 S.Ct. 2552, 2557 (1994).

More contempt-related provisions in the U.S. Attorney's Manual are assembled here.

As to how likely it is that Fitzgerald will charge Judith Miller with criminal contempt, I mentioned here that Patrick Fitzgerald included this in his court pleading (pdf) as to why Judith Miller should not get home detention or be sent to a federal prison camp:

The question is whether Miller would defy a final court order and commit the crime of contempt and thereby obstruct an investigation of persons who may have compromised classified information.

....If Miller persists in unlawfully depriving the grand jury of her prospective testimony and documents, which the Court of Appeals found to be “both critical and unobtainable from any other source” and necessary to an effort “to remedy[] a serious breach of the public trust,” she will frustrate the purpose of this national security investigation where the Court of Appeals noted the “gravity of the suspected crime.”

Just for fun, check out this press release from the Department of Justice in March, 2004, when they charged a man named John Vitello with criminal contempt, after he had served seven months of a civil contempt sentence for refusing to testify before the grand jury in an organized crime investigation. The press release concerns Mr. Vitello's decision to plead guilty to the criminal contempt charge.

VITELLO faces a maximum penalty of life in prison, an unlimited fine, and a five-year period of court-supervised release when he is sentenced by Judge Dorsey on June 4, 2004. VITELLO was released on bail pending sentencing.

Here's an earlier TalkLeft post on different standards used by different circuits in civil and criminal contempt cases.