Charlie Cook: “For sev­er­al weeks many Re­pub­lic­an can­did­ates and op­er­at­ives have been fret­ting that Don­ald Trump’s mis­be­got­ten can­did­acy could cause the bot­tom to fall out for GOP can­did­ates in Sen­ate, House, gubernat­ori­al, state le­gis­lat­ive, and oth­er down-bal­lot races. While their con­cerns were le­git­im­ate, it seemed too soon for the GOP to pan­ic. After all, the Don­ald Trump brand and the Re­pub­lic­an Party brand were cer­tainly not one and the same. Hil­lary Clin­ton’s neg­at­ives were so high that a land­slide seemed un­likely. And in quite a few races the Demo­crat­ic can­did­ates for some of these of­fices were not ex­actly of top shelf.”

“So while pan­ic should not be the GOP’s at­ti­tude right now, ex­treme worry seems ap­pro­pri­ate. The bot­tom has not fallen out for can­did­ates down the bal­lot, but many Re­pub­lic­an can­did­ates are see­ing their num­bers turn to purple or even blue. One vet­er­an Re­pub­lic­an poll­ster said privately on Monday morn­ing that he felt ‘sick to his stom­ach.’ In some cases, can­did­ates are weighed down by their as­so­ci­ation with Trump. In oth­er cases, Trump is caus­ing nor­mally stal­wart Re­pub­lic­an voters to lose heart. They see the GOP pres­id­en­tial nom­in­ee go­ing down in flames and don’t want to be part of a Hil­lary Clin­ton coron­a­tion, so they’re con­tem­plat­ing not vot­ing at all. When people re­port a lack of en­thu­si­asm about vot­ing, that of­ten res­ults in their drop­ping out as “likely voters” in opin­ion polls, caus­ing the op­pos­i­tion can­did­ate’s sup­port levels to bal­loon.”