Miller is in jail because she refused to testify before a GRAND JURY.
Novak - WHO OUTED PLAME (and thus commited the act which the Special Investigator is investigating) - and Cooper did not refuse to testify before the same Grand Jury, so they are free. Novak and Cooper were willing to testify because they were "released" from the oaths of secrecy by their sources.
If Miller had the same source or sources, then it is reasonable to assume that she would have received a release, too. The fact that she has not received a release indicates to me that she has other sources, or THAT SHE IS EITHER ONE OF NOVAK'S SOURCES - OR PERHAPS EVEN THE TARGET OF THE GRANDY JURY INVESTIGATION -- OR BOTH.
Miller is a LIKELY SOURCE because she VERY LIKELY knew Plame (and thorugh her Joe WIlson) and knew about her COVERT JOB, because Miller's LONGTIME BEAT - at the NYTIMES, and before, when she was a reporter living in DC and writing for the PROGRESSIVE, (a Left-wing outfit) - was WMD --- WHICH IS EXACTLY WHAT PLAME'S JOB DIRECTLY DEALT WITH.
If this is true, then Miller probably told Novak that she knew that Joe Wilson's claims (in a NYTIMES OP-ED piece - that he had been sent to Niger by Cheney, and that he had found nothing, and that this somehow proved that Bush 16 words in the 2002 SOTU were false) - were DISINFORMATION -- AND THAT SHE KNEW PLAME WAS A COVERT AGENT ON WMD, AND HAD PLAYED A MAJOR ROLE IN SENDING HIM TO NIGER, SPECIFICALLY TO DEBUNK THE AFRICA-SADDAM CONNECTION, (which was Plame's bias in the matter).
She probably told this to Novak [Update: or perhaps Rove] WITHOUT first getting him [them] to promise to shield her identity, so he probably testified that she was how he found out that Plame was in the CIA. Novak's lawyer probably WANTED Noval to testify as to this BECAUSE THE LAW EQUIRES THAT THE LEAKER GET HIS INFO FROM COVERT SOURCES, AND KNOW THAT THE INFO' IS SUPPOESED TO BE KEPT ECRET. If Novak got the info from Miller - and not someone at the CIA, then Novak is in the clear - AND MILLER IS ON THE HOT-SEAT.
And if this is the case, then her refusal to testify could be seen as an attempt to protect herself from indictment, or ostracization from her profession, and/or from the sources on her beat. OR TO PROTECT THE WILSON/PLAME'S.
[ASIDE: It must always be remembered that Wilson is a proven liar who misled the Senate, and whose assertion that Bush lied in his SOTU is TOTALLY FALSE; Bush's 16 words are as true today as they were then. Bush NEVER even said the word NIGER (or yellowcake) in his speech; Bush cited British intel' that Saddam had sought urnaium in AFRICA - a claim the 2004 Lord Butler report said was ACCURATE AND TRUE.]
UPDATE: JPOD at NRO discovers that Joe Wilson has issued a statement DEFENDING MILLER'S REFUSAL TO TESTIFY, and asks if Joe might not be Judith's source! GO THERE AND READ IT NOW!
UPDATE: AP (HAT TIP DRUDGE) IS REPORTING THAT NOVAK MIGHT HAVE BEEN ROVE'S SOURCE. SO... MAYBE MILLER WAS NOVAK'S SOURCE, AND WILSON MILLER'S SOURCE?