Terror Warning Tape?

This is a "For Your Discernment" post.

Drudge and others reporting that ABC News has received a Terror Warning Tape in which

The terrorist claims on tape the next attack will dwarf 9/11. "The streets will run with blood," and "America will mourn in silence" because they will be unable to count the number of the dead. Further claims: America has brought this on itself for electing George Bush who has made war on Islam by destroying the Taliban and making war on Al Qaeda.

ABCNEWS strongly denies holding the tape back from broadcast over political concerns during the last days of the election.

The CIA is reporting today that it cannot "authenticate" the tape.

More Drudge:

ABCNEWS obtained the tape from a source in Waziristan, Pakistan over the weekend, sources tells DRUDGE.

"We have been working 24 hours a day trying to authenticate [the tape]," a senior ABCNEWS source said Wednesday morning, dismissing a claim that ABC was planning to air portions of the video during Monday's WORLD NEWS TONIGHT.
The terrorist's face is concealed by a headdress, and he speaks in an American accent, making it difficult to identify the individual.

US intelligence officials believe the man on tape may be Adam Gadhan - aka Adam Pearlman, a California native who was highlighted by the FBI in May as an individual most likely to be involved in or have knowledge of the next al Qaeda attacks. According to the FBI, Gadahn, 25, attended al-Qaida training camps and served as an al-Qaida translator.

The disturbing tape runs an hour -- the man simply identifies himself as 'Assam the American.'

We have a few questions: What does it mean to "authenticate" a tape? What exactly is being authenticated, the source of the tape, the seriousness of the threat, or the actual identity of the speaker? Or is it something else?

Given the seriousness of the threat, isn't the most prudent action on the part of ABC to air portions of the tape? Which is more serious: report the story, and nothing happens, or fail to report, all hell breaks loose and people get hurt because of ABC's newfound concern for documentation? How much is the political climate interferring with news judgment and civic responsibility? Further, given the recent trend of CIA sources to diss the president, can we trust the spy agency to give us an objective analysis?

Thank God for Drudge and others who leak this stuff and get it out in the open. True, it may mean nothing at all, but as a journalist I've always believed that ultimately the people have a right to know what's going on.