This could be pretty big:

ABC News is reporting breaking news that John Edwards and his wife, Elizabeth, are holding a press conference Thursday at noon. No one yet knows why, but you don't mysteriously announce a press conference with your wife if it's good news. This comes on the heels of Edwards canceling a campaign appearance recently in order to attend a doctor's appointment with his wife, who was diagnosed with breast cancer in 2004.

It's probably true that you don't mysteriously call a press conference to announce good news, but it's important to remember that sometimes you do mysteriously call a press conference to announce nothing at all.

Update: Ezra Klein hears rumors that Edwards is planning to drop out. Say it ain't so, Jo[hn]!

Update #2: The big papers have joined the party, with a somewhat disheartening message: the Times quotes one "close family friend" as saying that the announcement "would affect, at least temporarily, the future of the campaign." While I suppose that's better than nothing ("at least temporarily" clearly suggests, if nothing else, the possibility that the campaign will continue in the long-term), it does seem uncomfortably likely that we're dealing with an announcement in the neighborhood of Aravosis Paradigm 3.

On the other hand, in an encouraging sign, Ezra Klein follows up his earlier post with this: "I am, happily, hearing more contradictory things now, as the campaign is apparently telling folks not to assume the worst." (How encouraging a sign that really is depends pretty heavily on how you define "the worst." If the worst is "Elizabeth has cancer," then we're in good shape; but if the worst is "I'm withdrawing from the race," then "not assum[ing] the worst" is entirely consistent with "I'm suspending the campaign indefinitely in order to take care of my wife.")