Partial VP-fronting, in which a verb is fronted with one argument, stranding the other one, is subject to a curious restriction in both Hebrew and English: The fronted VP-portion must be a potential independent VP in the language. It is shown that both incremental merger and remnant VP-fronting cannot explain the restriction, whereas an analysis incorporating late adjunction of the stranded argument can. Late adjunction, in turn, cannot apply too deeply, which explains why the same set of environments inaccessible to partial VP-fronting force adjunct reconstruction. The analysis implies that not only Spell-Out, but also interpretive constraints, like the Θ-Criterion, apply at the phase level. Furthermore, Condition A is shown to be another such constraint.