Opinion writer

Sen. Ron Johnson (R-Wis.) speaks with reporters in Green Bay, Wis., in May. (Scott Bauer/Associated Press)

Pollster Charlie Cook argues that “even if [Hillary] Clin­ton wins by a much lar­ger mar­gin than, say, [President] Obama’s win over [Mitt] Rom­ney four years ago, I don’t think the down-bal­lot im­plic­a­tions would be that huge.” Gerrymandered seats likely will save the House, he says, while, “the GOP ma­jor­ity is abso­lutely on the line; my guess it will end up 50-50, give or take a seat or two, but giv­en voters’ doubts about Clin­ton, the ‘don’t give Hil­lary Clin­ton a blank check’ ar­gu­ment may well be a polit­ic­ally po­tent one, and a lot of hold-their-noses Hil­lary voters may well look for a check and bal­ance down-bal­lot.” He adds the caveat that depressed GOP turnout could result in more down-ballot losses.

While all that seems eminently reasonable, we should keep in mind that the Republicans who are likely to lose in November — or lose their careers, thanks to their decision to join up with Donald Trump — have been among the strongest members of their party, pushing for reform while holding on to their conservative followers.

Starting with Indiana Gov. Mike Pence, a Trump defeat will, we strongly suspect, take him from governor to ex-politician. Politico reports:

“The danger for Pence is that people are going to say he sold out. They’re not going to say he’s the reason Trump lost. They’re going to say he sold out his principles to be part of that ticket,” said Andy Downs, director of the Mike Downs Center for Indiana Politics. “And if he’s viewed as someone who sold out, then he loses his base.”

Being a “good soldier” in service of a destructive, unhinged character who foments divisiveness is nothing to brag about.

The casualties in the Senate are likely to include (at least) Sens. Mark Kirk (R-Ill.) and Ron Johnson (R-Wis.). While Kirk would have had a hard uphill climb in any presidential year in a deep-blue state, Johnson arguably faces stronger headwinds due to Trump, who is trailing by 15 points in Wisconsin. The next most vulnerable incumbent is Sen. Kelly Ayotte (R-N.H.), regarded as a rising star and outspoken foreign-policy star, who is running ahead of Trump (who trails Clinton by 17 points in New Hampshire in the latest poll) but nevertheless is down 10 points to Gov. Maggie Hassan. Sen. Pat Toomey (R-Pa.) is down by 3 points in the latest Quinnipiac poll, no small feat considering that Trump is down by double digits in Pennsylvania in recent polling.

Even Sen. Marco Rubio (R-Fla.), who repeatedly embraced Trump over the summer, is now in a nip-and-tuck race with potential opponent Rep. Pat Murphy (D-Fla.) by only 3 points, equal to the margin of error, in the latest Quinnipiac poll. The poll’s director remarks, “At this stage of the campaign, Republican U.S. Senate candidates may be running against their own presidential nominee, Donald Trump, as much as they are against their Democratic opponents.” It’s hard for Rubio to do this after his on-again-off again embrace of Trump.

Consider, then, that along with Trump, the GOP could lose from its stable a pantheon of GOP favorites — two strong Midwesterners (Pence and Johnson), a woman with national-security credentials (Ayotte) and two blue-state GOP senators (Kirk and Toomey). It is not simply the numbers, although a Senate loss would be a blow, but also the quality of those at risk that make this such a painful year for Republicans. Trump will leave the party in shambles and without the presence of at least some of the people most capable of helping it get back on its feet.