This keeps coming up, particularly from Sanders supporters. Hillary Clinton's favorability ratings are net-negative, and on the low side for a nominee at this stage. This feeds into ideas such as "Clinton fatigue" and the general but poorly-specified notion that she is corrupt. Obviously, a candidate with a clean slate would do better, right?
No. Time for yet another trip down memory lane. Remember the 2008 campaign? Obama cleaned Hillary's clock, but Hillary refused to recognize reality, and kept campaigning based on the faulty premise that the superdelegates would give the nomination to her because she was obviously more electable than Barack Obama.
Santayana's words are ringing in my ears as I type. (Go look it up, kids).
Anyway, in the strange period between the time that Obama locked up the nomination and Clinton clued into reality, Republicans toyed with the idea that they could convince disaffected Hillary supporters to vote for McCain, if only they stopped accusing her of murder and stuff. (Vince Foster is famous again! Yay!) So, they started talking about how much they loved her grit and determination, and how she was speaking to the disaffected (read: white) voters in a way that Obama couldn't. Suddenly, Republicans loved Hillary!
That didn't work, but Clinton slid right into the job of Secretary of State, which was perfectly suited to keeping her name in the news, but in a relatively non-partisan context. That kept her approval ratings quite high, and indeed, higher than Obama's for pretty much his entire first term.
What happened next? Benghazi. Sorry, I meant, "BENGHAZI!!!!!" A group of terrorists attacked the US Embassy in Libya, and since embassies are under the authority of the Secretary of State, this obviously meant that Hillary personally ordered the attack because the Ambassador had uncovered evidence of her involvement in Vince Foster's death. Also, CHEM-TRAILS!!!
And this gets to the reason that Republican attention shifted to Benghazi. All of the actual accusations, like the "stand down" order were bullshit, but the event served as a pivot. The Republicans had spent four years talking up Hillary Clinton, and she was obviously going to be the next Democratic nominee. They needed to start talking her down. Hence, BENGHAZI!!!
What's really going on here is what we call elite signaling. Most voters are relatively uninformed. Thus, they rely on cues from politicians and media figures whom they trust to tell them how they should orient themselves. What follows is heavily influenced by a classic book called The Nature and Origins of Mass Opinion, by John Zaller. Great book. Go read it. After you finish reading this.
If Republicans hear their party leadership, along with everyone else, tell them that Hillary Clinton is wonderful for four years, they will accept those messages evaluate Clinton more favorably because of the uniformity of messages. Many Republicans would still reject those messages because she is still a Democrat, and there are lots of residual negative cues, but Republicans heard positive signals about Hillary Clinton from their own party for long enough to erode some of the negative evaluations. That ended in 2012 when the party shifted back towards negative signals. For the last four years, Republicans, and independents too, have heard a nonstop barrage of negative messages about Hillary Clinton. Opinion followed.
Was she an intrinsically stronger or more unifying figure in, say, 2010? No, she just wasn't being attacked. Right now, opinions of her are just locked into where they would be after a campaign because she has been involved in a campaign for four years. She starts the campaign with higher negatives than normal candidates because the campaign is basically done. There is no room left for new messages to affect her status.
Contrast that with Sanders, whom Clinton stopped attacking long ago, and whom Republicans have never bothered to attack in any significant way. Most voters know nothing about him. Should we really be surprised that the candidate who hasn't been attacked much at all by the opposing party doesn't have those negative opinions among opposing partisans locked in?
Presidential campaigns are brutally negative. What political junkies (and I'm certainly one) can easily forget is that while we know a lot about every major candidate in the primaries, most voters aren't paying any attention yet. If you are reading this blog, there is a high probability that you can tell me a bunch of stuff about Chris Christie. Most voters can't. Most voters begin the general election campaign in ignorance of any non-incumbent. And with a negative campaign, there is nowhere to go but down. You cannot assume that a candidate would end a general election campaign with public evaluations comparable to what they have before the campaign because the campaign hasn't signaled evaluations yet.
I wrote a while back that this will be the most entertaining but pointless general election campaign ever. I stand by that.