I know Democrats are 0 for 4 in special elections. But Cook Report has Democrats outperforming the past in red districts that they write the House really is in play. If Democrats keep performing this way, Cook writes that Dems pick up 80 seats!
There is an axiom if the President has an approval rate below 50% in a by-election,the opposition picks up at least 36 seats in the House. Even if over, lose some seats.