It’s well known that when they do these multi candidates vs incumbent. The results get severely skewed. That is why Palin does so bad. They know she’s the biggest threat so the supporters of Romney, Gingrich, Bachmann, etc all go against Palin and say they will vote for Obama over her - just to skew results, to keep up the meme that she’s unelectable.
The bottomline, whoever emerges as the GOP nominee will start out with about 47-48% of vote and then go on to trounce Obama.
The bottom line is that Sarah Palin's poll numbers are so extremely toxic that her endorsed GOP candidate in her own State of Alaska lost a U.S. Senate election to a WRITE-IN candidate with a hard to spell name.
In politics, you simply can't do any worse than that.
Some candidates are far more toxic than others and Sarah Palin, outside of her adoring 8% of all voters, has devastatingly toxic poll numbers.
The GOP needs a conservative candidate with poll numbers that are not in the Donald Trump "joke candidate" range.