Polling has consistently shown that Donald Trump is the least electable candidate in the Republican field. At present Donald Trump trails Hillary Clinton by 9.3 points in polls of general election voters, and this gap has remained remarkably constant. By contrast, Ted Cruz trails Hillary by an average of 2.3 points, and has often led Clinton in the polls. John Kasich has consistently led Hillary Clinton, and at present leads her by 7.8 points.

Among presidential candidates, Donald Trump's unfavorable ratings are historic. According to a Washington Post/ABC poll, 67% of Americans view Trump unfavorably, including 53% who view him very unfavorably. Conventional wisdom holds that a politicians unfavorable rating sets a hard ceiling on their share of the vote. Once voters have an unfavorable opinion of a politician, they won't vote for them.

Really, this is just scratching the surface of how bad a general election candidate Trump is. No party has ever nominated a candidate who was both this unpopular, and divisive within their own party. Polls show a significant number of Republicans who would either vote for Hillary, go third party, or stay home, if Trump was the nominee.

Trump is such a bad general election candidate that his nomination could threaten Republican control of the House. Turnout in presidential elections is typically much higher than mid-terms. If enough Republicans stay home on election day, a Democratic takeover of the House is not out of the question. Larry Sabato's website offers a detailed analysis.

Despite this, some people, like former New York mayor Rudolph Giuliani, are optimistic about Trump. He described it to Megyn Kelly, “Cruz is a fastball that the Democrats have hit out of the park, whenever they want, straight right wing, very doctrinaire, very easy to beat, can't win any of the Northeast, can't win the west. Trump is a Mariano Riviera cut fastball... He's unexpected, Hillary doesn't have a rule book for running against Donald Trump.”

Excluding one-issue voters like Ann Coulter and Mickey Kaus, there are two basic types of Trump optimists. The first type consists of Trump true-believers, who love Trump and believe that he will be able to win over the doubters come November. This includes people like Scott Adams, who famously predicted that Trump would win in a historic landslide.

The second type is a tad more cynical. These are people like Giuliani, socially liberal blue-state Republicans who want to move the party away from divisive cultural issues such as abortion and gay marriage. They see the socially conservative wing of the party as an albatross that hurts the Republican brand in places like New York, or Illinois.

It would be easy to dismiss this view as the opinion of a small faction within the party, but consider how frustrated someone like Giuliani is. Until Giuliani, the Republicans had been shut out of power for decades in New York City. When he witnesses average middle-class voters supporting Bill De Blasio over Joe Lhota, is it hard to understand how he could come to see people like Ted Cruz as a boat anchor?

And Trump has been keen to feed the fantasies of people like Giuliani, repeatedly talking about how he will “open up the map” by competing in places like Michigan and New York. In actuality, polls show Trump losing his home state to Hillary by twenty points.

This is where the Trump fantasy meets the Trump reality. Trump optimists believe that Trump has a broad appeal and will compete in states Republican presidential candidates generally don't compete in. Trump's poll numbers tell a completely different story; Trump optimists place more faith in their own gut feelings.