Because a partisan court is a bad thing in general
Regardless of which side it supports
Generally, justices tend to be moderates, even when nominated by partisan presidents
e.g. Kennedy was appointed by Reagan
The supreme court has long-term power and sets precedents
And its the strongest defense against authoritarianism
As such, a 4-4-1 is a great thing there
Because it allows very constitutional court decisions
And another little thing - a partisan court will definitely put the country into the final phase of the culture war
