It suggests it, but it‘s far from clear cut or obvious. I think there are a few things going on. One, Trump is certainly wrecking the Republican brand. Not only is he on course to lose, boosting the Democrat share of the vote, but he is attacking other Republicans for not supporting him, making it less likely his own supporters will vote for them. That’s why other Republicans are so worried, they face the horrible choice of backing Trump and so associating themselves with his madness, or opposing him and inviting his attacks.gumboot wrote:Americans do all their voting at once, don't they? So if disillusioned Republicans sit this one out, does that suggest a Democrat advantage in Congress?
On the other hand though there may be some voters who deliberately split their vote, so vote Clinton for president but Republican for Congress. This may be to balance things out, or as they are deep down Republican but cannot bring themselves to vote for Trump. It’s unclear how significant this is though; it may have more of an impact in years when there isn’t a presidential election, and the party in the Whitehouse usually loses seats.
Another factor is the built-in bias that benefits Republicans. Because of gerrymandering they have more safe seats than Democrats, and it’s quite possible for Democrats to get more votes but Republicans get more seats in the House or Representatives. There’s no independent Boundary Commission like ours to fix this, it is up to highly partisan state legislatures where the boundaries are drawn.

