CNN  — 

First things first: The theme song of the week is Curb Your Enthusiasm.

Poll of the week: A new ABC News/Washington Post poll finds former Vice President Joe Biden at 53% to President Donald Trump’s 41% nationally among registered voters.

Biden’s advantage in the average of all polls puts Biden above 50% and ahead by around 9 points, depending on how you exactly average.

What’s the point: Trump enters the Republican National Convention in an unusual position for an incumbent: trailing. It’s not just that he’s trailing, though; he’s trailing by a lot.

If Trump is to come back and win this election, he’s going to have to rewrite the record books.

There have been only three incumbents who were down by more than a point at the beginning of the convention period since 1940: Harry Truman in 1948, Gerald Ford in 1976 and Jimmy Carter in 1980. Only Truman, down by about 10 points, had a deficit that matched Trump’s at the current time. But even Truman didn’t have an opponent who was already pulling in more than half the vote.

The potentially good news for Trump is that because he’s in an unprecedented position, it’s difficult to ascertain his true chance of a comeback, especially during a global pandemic. Further, it’s noteworthy that Truman actually did win in 1948. Ford closed his 7-point deficit pre-conventions against Carter in 1976, but still lost by 2 points.

One way in which Trump is clearly in a worse position than either Truman or Ford is his own popularity. Truman’s net approval rating (approve - disapprove) was only about -5 points on the eve of the conventions in 1948. Ford’s was actually positive. Trump’s net approval rating is about -12 points.

The two presidents with net approval ratings in the negative double digits going into the conventions since 1940 both lost. In fact, Carter in 1980 and George H.W. Bush were the two presidents who lost reelection by the largest margins in the polling era.

View 2020 presidential election polling

A strong convention for Trump would be one in which he brings up his popularity.

Still, being unpopular and winning wouldn’t be anything new for Trump. He took the 2016 election, even as he had a -22 point net favorability rating (favorable - unfavorable) in the exit poll.

And indeed, Trump’s running slightly ahead of where you’d expect him to be against Biden based on his net favorability (or approval) rating. He’s down by 9 points instead of double-digits.

The difference between Trump’s own popularity and the ballot test, though, is considerably smaller than it was in 2016. It’s only about 5 points or less this year, not the 20 points it was last election cycle.

Trump’s problem is two-fold.

First, Biden’s simply more popular than Hillary Clinton was, so Trump can’t count on a very unpopular opponent to play off.

Second, Trump can’t count on the votes of those who dislike both candidates. Biden’s winning them by a considerable margin. In the most recent NPR/PBS NewsHour/Marist College poll, the margin was about 20 points in his favor. Trump won those who disliked both candidates in 2016 by nearly 20 points.

This time around, this group who dislikes both candidates is far more likely to be younger voters who despise Trump.

Even if he can’t get voters to like him more, a good convention for Trump would be one in which he makes Biden less liked or at a minimum makes those who dislike both candidates to give Trump a second look.

Because unless something changes in the final months of this election, Trump is unlikely to recreate the magic he did in 2016.