>>but in many cases these laws can be ambiguous and there can be varying interpretations - which can result in appeals....it boils down to a liberal or conservative interpretation - thus in theory the court *should* lean the way of the population.

If Congress passes ambiguous laws that are interpreted by the SC contrary to congressional or popular intent, then it is the responsibility of Congress to fix that. Not the SC and not POTUS; Congress- popularly elected Congress. The only people who would benefit from appointed lifetime SC judges undoing the will of the people, are those whose intent is unlikely to find favour with popularly elected representatives, who therefore hope to weasel things into place via their activists. As I keep saying, there's no evidence Kavanaugh is an activist as you so fear, his credentials as dryest of the dry legalist survived the unprecedented process the Democrats threw at him and ought to be reassuring for all who believe in the US model. So all these protestations of fear betray the intentions of others IMHO.