  For $E$ a presheaf of spectra on the category of smooth $k$-schemes
satisfying Nisnevich excision, we prove that the canonical map from the
algebraic singular complex of the theory $E$ with quasi-finite supports to the
theory $E$ with supports intersecting all the faces properly is a weak
equivalence on smooth $k$-schemes that are affine or projective. This
establishes some cases of a conjecture of Marc Levine.
