House Generic Ballot is the metric that counts for House 2018 (more than Trump approval on available daily from Gallup)
What you are looking for is a double digit spread between Democrats and Republicans nationally (AHCA certainly helped, but they had to do it for tax cuts that they think helps and they think “Obamacare relief” is enough defense so we shall see) in the House Generic Ballot and Trump approval in the 30s. It’s still seems like 40–40–20 with the 20 breaking for their pocketbook absent a major foreign policy crisis that we are losing is how this plays out.
Polls and chart for 2018 National House Race. See the latest estimates and poll results at HuffPost Pollster.elections.huffingtonpost.com
RealClearPolitics - Election Other - 2018 Generic Congressional Votewww.realclearpolitics.com