As others have pointed out, Trump may not even receive the full five-point boost from his scaled-down convention. We live in an increasingly polarized era, and the number of swing voters who can be persuaded by an inspiring convention speech is decreasing. Between 1968 and 1996, the convention bounce was six points on average, and between 2000 and 2016 it was only three points. Plus, fully or partially virtual conventions likely won’t be as visually impressive as the packed arenas of previous cycles, especially if apolitical swing voters opt for Netflix or whatever professional sports are still airing instead of politics.
Additionally, the Republican convention won’t happen in a vacuum. A week before Trump and the Republicans meet, Democrats will hold their own convention, airing speeches for two hours every night. That doesn’t sound like enthralling programming, but the story the convention tells could still help define Biden in voters’ minds. As political scientists David Broockman and Joshua Kalla have demonstrated, pro-Biden ads are more likely to move voters than anti-Trump ads. A week of free airtime in which to sell the former vice president could help solidify Biden’s lead before Trump’s convention.
And even if Trump can improve his position at his convention — in 2016, he earned a slightly larger convention bump than Hillary Clinton per the UCSB data — he wouldn’t be out of the woods. Trump lacks impulse control and could easily derail any rosy news cycles that follow the convention. In the aftermath of his 2016 convention, he picked a protracted, ugly fight with Khizr and Ghazala Khan, the parents of a slain U.S. soldier.