Dem
51
GOP
49
Having a slight plurality of the voters for you is fine and dandy (see above), but it doesn't help if they aren't registered and don't vote. For almost all of this year, in North Carolina and Pennsylvania, net new weekly Republican registrations were outpacing Democratic ones. When Biden dropped out and Harris took over, suddenly it switched, with new Democratic registrations outpacing Republican ones, as shown in this bar graph:
As you can see, the Republican National Convention gave the GOP a big spike in registrations. The Democrats are almost certainly going to get one next week. What will be interesting is whether it matches the Republican one.
What the chart doesn't show is that the new Democratic registrations are primarily women and young voters. These are groups that lean left and which Kamala Harris will be targeting hard. Of course, a net few hundred registrations per week does not a victory make, but it is a sign of enthusiasm. (V)