How many Democrat seats are at a high level of risk to switch to Republican?
Unknown how many Democrat seats at risk, but
it is more difficult to "get out the vote" in a non-presidential election year.
Many voters will get complacent and fail to show up to vote.
Complacency is the conservative challenge, not the Democrats.
Volunteer to rally the troops !
None. He lists two as toss-ups and a couple as only tilting Democrat. Three issues are apparently feeding the chance of Democrat pickups. The first is the tax bill and what the loss of the SALT deduction does to Republicans in Illinois, Pennsylvania, New York, California, and New Jersey. The second is the Pennsylvania redistricting. And the third are the large number of retirements removing any advantage an incumbent might have. On the other hand the election is over seven months away. A lot can happen in that time.
This looks rough http://cookpolitical.com/ratings/house-race-ratings
1R likely go D
6 lean to D
22 toss up R
19 Lean R