Justice Alito announced the judgment of the Court in Mitchell v. Wisconsin and delivered an opinion joined by the Chief Justice and Justices Breyer and Kavanaugh. Justice Thomas concurred in the judgment. Justice Sotomayor filed a dissenting opinion, joined by Justices Ginsburg and Kagan. Justice Gorsuch also filed a dissenting opinion.
So what does it say? It is a bit confusing, but it appears that if you are drunk and passed out that is an exigent circumstance and there is not a need for a search warrant. The plurality of justices did not address whether if you are not passed out but tell the officer you don’t want to take a test whether that too is an exigent circumstance.