Because the states were taking it up first.
In the case of Pennsylvania, the state GOP went to the federal circuit court, which turned them down. Then they went to the Supreme Court arguing Article II Section 1 powers, and Roberts declined to hear it.
Justice Thomas said they weren't ruling on the merits of the case, just the procedures of it, so he left the door open for the Supreme Court to hear it on the merits once the voting was over.
That's why President Trump is pushing it now.
-PJ
Oh, ok. I hope things look better tomorrow.