We know now that it was an entrapment operation. The Russian lawyer lady had been previously banned from entering the country. She was given a probationary visa in the winter of 2015 and then granted a business visa later in the spring of 2016. To get a business visa so soon after being on probation is highly unusual. She was in the country with the blessing of DOJ/DOS. She met with Glen Simpson/Fusion GPS before and after the tower meeting.
The State Department signed right off on that. Funny how the State Department was involved in the non-standard channels to disseminate this "Kompromat" into the US system.
Likely helped along by Brennan at the CIA too.