Predictions: Senate

The Senate may be controlled by the Democrats, but likely by a very slim margin.  Based on our history, a 50/50 split or 51/49 split is going to be unstable.  Among the events which can affect passage of a specific bill and/or control of the Senate (disregarding the likelihood of a filibuster and the need for 60 votes)

• any individual senator can hold out for his or her favorite project issue (we saw that in the ACA negotiations--the senators from LA, AR, and NE at different times held out for something special)
• a senator may switch parties
• special elections to fill vacancies (first of all--the VA seat Kaine now holds) from resignations or death. Note most governors are Republicans, in cases where they have authority.  Such elections will attract gobs of money.