Here is a copy of the warrant application.
I wondered about the definition of 'probable cause.' The statements in the application sound very definite, but how definite is it? After all, this is prior to the full investigation with surveillance. While researching, I found this quote from the governing case Illinois v. Gates:
"Probable" cause means that the investigator has to show "a fair probability," not a certainty or near-certainty.So, it seems that the level of certainty is not without a doubt or beyond a reasonable doubt, or guaranteed to be true under penalty of perjury. It is 'fair probability.'
Some blowhard on the web (there are a few) claimed that the FISA warrant was perjured, and the person writing the warrant has to swear to the veracity of all the information. I have my doubts that he knows the law well enough to make such a claim. There is also the matter of actual practice of how warrants are written, what is the usual language, what is understood between the legal parties. So it's armchair speculation to attack or defend this warrant unless you have knowledge and experience with warrants.
I've done a bit of speculation. I've read that Brennan (some CIA honcho) said there were plenty of allied intelligence services warning about Trump. Is this true? I certainly don't know, and I'd like to know more, but I don't expect the intelligence services to just cough up the info. Maybe there were a lot of rumors from sources that are generally pretty responsible. If so, it's too bad they weren't mentioned in the warrant. Of course, maybe they were mentioned, somewhere in the 13 blacked out pages related to Page. Those 13 pages could contain a lot of info that hasn't ever been openly published, but we certainly don't know. Those who assume that dossier was the only info used for the warrant are assuming that there's nothing in those pages. I think it's an incorrect assumption. If it was about the dossier, why would it have been blacked out when other info about the dossier wasn't?
I'll also say that on reflection, it seems like a very bad idea to hire someone to pump Russians (or any enemy or questionable source) for dirt on your opponent. It looks like Steele and Clinton got played to a certain extent, but they also ended up looking very scummy. That's why neither Clinton nor the FBI revealed their connection to Steele. If you have to hide your connections, maybe you shouldn't have them. That applies to Mike Flynn, Jeff Sessions, and Hillary Clinton too. Anything you try to hide, it ain't going to stay hidden. Remember that.
Extras. I was researching probable cause and read most of this ruling. A good learning experience because of the clarity--or maybe I simply skipped over the convoluted parts.
How the Steele dossier looks in retrospect. Some of the Steele dossier was correct and some wasn't when you compare it to the Mueller report.