I can speak of this first hand although my experience is from 2008 to 2013. Tulsi was given an assessment which has a history going back to 2007. My agency basically operated a sliding scale with the time to build a bomb in six months. Then when six months passed, it was another six months and so forth. Two major things precluded an honest assessment: Obama's nuclear deal...er bribe, and the fact we were in Iraq. We couldn't give cause for us or the IDF to take action. For one thing, we controlled the airspace of Iraq and we weren't going to let the IAF use it. I can't begin to describe the political ins/outs and the backstabbing involved.
As to Tulsi, I had my misgivings about her from the beginning. Not because she is dishonest or scheming, etc., but because she is naive