The supreme court, having ruled that it has the power to decide what the constitution says, is pretty much immune to the text of the constitution. They have pretty well shot down the 4th amendment already.
No, the amendment changes what the constitution says. As TKG said, that's what amendments do. They can only be superseded by a later amendment (See 18th & 21st amendments).
That's not much of a check. Deciding who can get in is nice, but once they're in, they're not accountable to anybody. The court is entirely UNchecked.