To be honest, it's hard to game out exactly how this is going to go down but, as always, the data we currently have are a helpful guide. As Harry Enten points out, while the he polling data could change over time, right now it looks the situation could well help Biden more than Trump.
"A new Marquette University Law School poll paints the landscape well. Nationally, it finds that 59% of Biden voters say that appointing the next Supreme Court justice is very important to their vote. Compare that with only 51% of Trump voters.
This finding matches what we saw in a CNN/SSRS poll last month. In that poll, 78% of Biden backers told pollsters that nominating the next justice was extremely or very important to their vote. That compared with 64% of Trump supporters. (It was 47% Biden supporters and 32% Trump supporters who said it was extremely important.)
Compare these numbers to what we saw heading into the 2016 election. The final CNN/ORC poll in that cycle showed that 58% of Trump supporters said that nominating the next Supreme Court justice was extremely important to their vote, while only 46% of Hillary Clinton voters said the same. In the 2016 exit poll, Trump beat Clinton by a 15 point margin among those who put Supreme Court appointments as the most important factor to their vote.
In other words, it seems, at least initially, that unlike in 2016, a Supreme Court nominating fight could be more of a motivating factor for Democrats than Republicans....
New York Times and Siena College polled voters this week in Arizona, Maine and North Carolina about their views of the presidential candidates and the Supreme Court.
Biden was more trusted to pick a nominee in the average of all three states by a 53% to 41% margin. That was actually larger than his average lead against Trump in the horserace of 50% to 41% in the three states.
This phenomenon of Biden getting slightly more favorable numbers on who should pick the next Supreme Court nominee than in the horserace matches what a recent Fox News national poll found.
But perhaps more interesting is what the New York Times found among persuadable voters (i.e. those who said they could change their mind or were not backing either Biden or Trump). They preferred Biden to pick the next nominee by a 49% to 31% margin.
And among those voters who might not vote (i.e. those who said were less than very likely to cast a ballot), Biden led Trump by a 52% to 23% margin on who would be better at picking the next Supreme Court justice."