But Trump doing badly can hurt Republicans down ballot. While I don't think many people will vote Democratic down ballot because they dislike Donald Trump, Trump could encourage more Democrats to vote and discourage Republicans. Trump likely will hurt Republicans, even if it's only by a point or two.
Democrats have a candidate who is also unpopular. A candidate with her favorability rating usually couldn't get elected President. Except that Americans like Donald Trump less. Only 11% of Americans find Hillary Clinton honest and trustworthy. Guy Benson over at Townhall does a good job chronicling this.
Republicans have to twist themselves to distance themselves from Trump, often saying phrases like, "I support the nominee." To them saying "Donald Trump" is akin to saying Voldemort. It isn't hard for these candidates to criticize what Trump says or disavow Trump's policies. Donald Trump has no ties to the Republican party or Republican candidates, making it difficult to say a candidate is lock step with Trump. It can be tough to tie someone voters have voted for again and again to someone who just entered politics.
Democrats, on the other hand, have supported Hillary Clinton for years, many of them dismissing criticism of her as right wing lies. After the State Department Inspector General report and the James Comey press conference it's difficult to defend Clinton as honest and trustworthy. Clinton is a long time mainstream Democrat. Unlike Trump, few Democrats want to distance themselves from her. Because the Clintons hold great power in the Democratic party and are known to be unforgiving to those that cross them, distancing yourself from Hillary Clinton could be bad for a candidate's long-term success.
I'd think that Republicans would want to do the same as Democrats are doing and tie down ballot Democrats to Hillary Clinton. They haven't. And the media doesn't ask Democrats about things Hillary Clinton has said and done like they do with Republicans and Trump. That changed when CNN asked Democratic New Hampshire Senate candidate Maggie Hasnan three times if Hillary Clinton was honest and trustworthy.
Hasnan stands by Clinton, giving reasons why she supports her party's nominee. But she wouldn't say Clinton was honest. Later her campaign said that Hasnan believes Clinton is honest and trustworthy. So Hasnan is willing to say Clinton is honest but not say it on camera. This is probably because if she does Kelly Ayotte could run an ad with Hasnan saying Clinton is honest followed by Clinton lying. Hasnan won't let that happen.
Down ballot Democrats probably want to talk about Hillary Clinton only slightly more than down ballot Republicans want to talk about Donald Trump. They sure don't want to answer questions about Clinton's honesty or whether Clinton put national security in danger. Democrats are going to tie Republicans to Trump. Will Republicans tie Democrats to Clinton?