Mitch's views have certainly evolved over time.
"As a young lawyer, McConnell had argued in an academic journal that politics should play no part in Supreme Court picks; the only thing that mattered was if the nominee was professionally qualified.
In 2016, though, he said it made no difference how qualified Garland, a highly respected moderate judge, was."https://www.newyorker.com/magazine/2020/04/20/how-mitch-mcconnell-became-trumps-enabler-in-chiefHis current reasoning is rather inventive;
2016 - Democrat House, Republican Senate, Democrat President = no vote
2020 - Democrat House, Republican Senate, Republican President = vote
