If the Dems do flip the House, then MS and TX can go Democratic
What one has to do with the other? Especially considering that most of the seats needed to lead the Dems to a majority are in blue coastal states?
I think that what he means is, for example, if the Democrats do well in Texas by winning congressional seats like TX-07, TX-21, TX-23 and TX-32 (all Republican House seats in Texas that are considered as toss-ups), then there is clearly hope for Beto O'Rourke to defeat Ted Cruz in the senatorial race in Texas.
https://www.270towin.com/2018-house-election/