Here's a less technical, but exceedingly-clear, explanation of what is at stake in this debate, also excerpted and transcribed from Monday's ABA forum [see my comment in the preceding thread for the more-technical explanation of former (and one current DOJ) Executive Branch experts of the underlying facts of the FISA debate].

Kate Martin, Director of the Center for National Security Studies, 3/3/08:

"Secondly, the surveillance that's at issue here [in both RESTORE and the Rockefeller bill] is - and we have to remember this - surveillance of telephone conversations and email communications between individuals located overseas and Americans and others located in the United States. And it's surveillance using the telecommunications infrastructure located in the United States; it's surveillance under which the government goes to the telecommunications companies located in the U.S. and asks for access to their facilities.

[..paragraph break..]

It is what has classically been understood as the core of the Fourth Amendment: it's the government acquiring the communications of Americans talking with people overseas and doing so from U.S. telecommunications facilities located in the United States. And while we can debate what the standards should be, we should start with that understanding, I think.

It covers not only acquisition of the contents of those communications, but it covers what [is] pen register and trap and trace information. It is not limited to conversations by terrorists. In fact, it's not limited to communications relating to terrorism, despite the rhetoric of some [] administration officials.

[snip]

Now what FISA had required, of course, was a [FISA] court order based on probable cause [not of a committed crime, but of evidence of foreign power agency or contact by a U.S. person in America] if you wanted to go to the telecommunications facilities in the United States and knowingly acquire the communications of an American with someone overseas. The House bill [RESTORE] does not require that - it doesn't require probable cause. It does, however [unlike the Rockefeller bill], require a [broad-based, sweeping, but prior] court authorization...

[snip]

But secondly, the court authorization, I think, is important - and I'll end with this point - because this is something I think that has not been discussed enough. It's not simply because a court involvement ensures that the rules that apply to the surveillance are being followed. [snip] But court authorization plays another very important role. Which is that, as I read the Senate bill, the DNI and the Attorney General are given the authority to go directly to the telecommunications providers and say: 'We are targeting Al Qaeda, we are targeting these individuals overseas, and give us access to your facilities so that we may take from the stream of communications going across the network, those communications which we believe are necessary to carry out our legitimate foreign intelligence purposes.'

Under the FISAct and under a regime that has a court authorization of surveillance, the court issued an order to the telecommunications providers which said: 'Give the government access to the following communications, give the government access, or whatever kind of access they need, in order to get everything from this area of Pakistan.' But it did not say: 'Give the government access to the telecommunications infrastructure' - and if, as I believe it does, that's the effect of the Senate bill, we are looking at a revolutionary change in the way the government conducts surveillance of Americans." - Kate Martin, 3/3/08

http://www.c-spanarchives.org/library/index.php?main_page=product_video_info&products_id=203407-1&highlight=surveillance

To get away with this "revolution" that effectively repeals the Fourth Amendment with regard to our private communications with everyone abroad, without benefit of a constitutional amendment, the Congress and president must bar the Judicial Branch from hearing or ruling on this "revolution." Enter: "retroactive immunity," which would effectively block American citizens from challenging in court their government's end-run of the Fourth Amendment, by executing a parallel end-run of the separation of powers so as to usurp the role of the Judicial Branch, as Congress and the president try to avoid being overruled by the judiciary on their cynical, corrupt, bad faith effective repeal of the 1978 FISA statute and our Fourth Amendment privacy protections.

P.S. Chris Dodd has promised to continue his opposition to a flawed 'conference committee' product. Note that his ability to block such a product dramatically improves shortly before a Congressional recess, which will be the case next week (it's the last week of work before Congress takes at least a couple of weeks off). He may not have to filibuster next week (but instead simply object to Unanimous Consent requests) to successfully push any final action and seriously-taxing filibuster off until after the upcoming recess.