He's winning! Really!

Republican Donald Trump should win the presidency by a slim margin according to a model that has accurately predicted the popular vote since 1988.

Using several standards to make his prediction, Alan Abramowitz's "Time for Change" model done for the University of Virginia's Center for Politics "Crystal Ball" shows Trump winning 51.4 percent to 48.6 percent for Hillary Clinton.

He added that the model shows a 66 percent chance of a Trump victory.

"Based on a predicted vote share of 48.6 percent for the incumbent party, these results indicate that Trump should be a clear but not overwhelming favorite to defeat Clinton: There should be about a 66 percent chance of a Republican victory," Abramowitz added.

The Time for Change forecasting model has correctly predicted the winner of the national popular vote in every presidential election since 1988. This model is based on three predictors — the incumbent president’s approval rating at midyear (late June or early July) in the Gallup Poll, the growth rate of real GDP in the second quarter of the election year, and whether the incumbent president’s party has held the White House for one term or more than one term. Using these three predictors, it is possible to forecast the incumbent party’s share of the major party vote with a high degree of accuracy around three months before Election Day.
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Despite the excellent track record of the Time for Change model, there are good reasons to be skeptical about the 2016 forecast. For one thing, the overwhelming majority of national polls during the spring and summer of 2016 have shown Clinton leading Trump. National polls completed shortly before and after the national party conventions gave Clinton an average lead of about five percentage points, and Clinton is up by about eight points now. Beyond the poll results, the Time for Change forecasting model is based on two crucial assumptions — first, that both major parties will nominate mainstream candidates capable of unifying their parties and, second, that the candidates will conduct equally effective campaigns so that the overall outcome will closely reflect the “fundamentals” incorporated in the model.
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The nomination of Trump by the Republican Party in 2016 appears to violate both of the Time for Change model’s key assumptions. Trump is clearly not a mainstream Republican and he does not appear to be running a competent campaign — he has lagged far behind Clinton in both fundraising and grassroots organizing in the swing states, and his rhetoric on the campaign trail has frequently brought sharp criticism from prominent Republicans as well as Democrats. In fact, there has never been a major party nominee like Trump — a reality TV star and wealthy businessman with no longstanding ties to the Republican Party, no political experience, and a penchant for insulting major voting groups. As a result, many prominent Republican leaders, including the last two Republican presidents, and the party’s 2012 nominee have refused to endorse Trump...

The question is how much the Republican Party’s nomination of Trump will move the needle away from its slight tilt toward the GOP based on the fundamentals in 2016. There is no way to answer this question until after the election. Based on the results of other recent presidential elections, however, as well as Trump’s extraordinary unpopularity, it appears very likely that the Republican vote share will fall several points below what would be expected if the GOP had nominated a mainstream candidate and that candidate had run a reasonably competent campaign. Therefore, despite the prediction of the Time for Change model, Clinton should probably be considered a strong favorite to win the 2016 presidential election as suggested by the results of recent national and state polls.