Another update on Sen. Tim Johnson's condition. Earlier we passed on the statement from the senator's office that tests showed he had not had a stroke or a heart attack.

However, CBS now has a report out which repeats that statement and then follows with this: "Sources close to the situation tell CBS News the situation is definitely not good."

I'm way out of my depth here in terms of what other conditions could be in play if it's true that a stroke has been ruled out. But the additional line from CBS is both troublingly ambiguous and ominous.

From what I can tell CBS is the only news outlet reporting something like this in the background. There's no point in my speculating. I'll just pass it on. We'll try to bring you more as we hear it.

Late Update: This report from NBC notes the conflicting accounts of what is happening.