Certainly you are right that investigations can be or become politically-driven messes.
I don't agree that the Democrats are the experts, but I don't want to go off on a long-winder with you on this.
*Absolutely regardless* of one's worry about politics, this is a serious question and must be investigated. One rumor I've heard said that the intel specifically mentioned American and United Airlines. This has to be confirmed or denied. It's really really important.
Personally, I doubt very much that provocative intel reached the pres and he chose to ignore it. This is probably more a question of the product getting lost in the CIA/NSA or wherever.
I don't think you have anything to worry about, unless some bonehead starts to play cover-up.