Oh they very much do. Legislative intent is a major factor that many judges consider when enforcing legislation. Intent often has a very big impact on consequence.

IANAL, but this could cut both ways, couldn't it? If the judge decides the effect is different than the intent, she could either say "the intent is valid so let's ignore the effects" (what you seem to advocate here) or "the effects are not what was intended so until the legislative branch makes a change we'll use the following interpretation in order to make the effects more like the intent". There may be a standard way of deciding between these two alternatives, but I don't know it.