This has happened in 5 consecutive elections, all the way back to 2000. It may actually go back further but I'm too lazy to calculate.

The way I operationalize this is with the r^2 for predicting the two-way Senate vote with the two-way Presidential vote. In 2000, it was 20.6%. In 2004, it was 39.5%. In 2008, it was 48.8%. In 2012, it was 50.7%. In 2016, it was 82.6%. And in 2020, it was a remarkable 91.9%. If 2024's r^2 is higher than 2020's value, this market will resolve to Yes. If it is lower, the market will resolve to no.

Here's a visualization of this trend:

There are some Senate races where candidates will be extremely reliant on relatively high levels of ticket splitting (e.g. Montana, Ohio, Maryland) and I'm fairly skeptical.

All numbers are my own calculations and it's entirely possible I made a mistake somewhere, so when it's time to resolve the market I'll double and triple check the 2020 and 2024 numbers.