The most perplexing part of this decision isn't really in the decision at all:
The Stay: Saturday 9 December, 2000. 14:40 (warning: PDF)
The Stay was issued by five Justices (Rehnquist, O'Connor, Scalia, Kennedy and Thomas) and ordered a stop to the recount until it could rule.
Stays are only issued in circumstances where irreparable and extraordinary harm would be done to the petitioner. This has to mean that the Court "determined" that Bush was indeed
almost certainly the winner, because otherwise an equally valid argument can be made by Gore that the counting should go on to establish that he had won.
Unusually, we are provided with concurrences/dissents to the Stay:
The Justices would later decide 7-2 that the count as conducted was unfair and therefore unconstitutional. However, if a full and fair recount had been possible, one which Gore had won, then this stay has cast a cloud over his legitimacy as the elected President.
Indeed, as Justice Stevens noted “the entry of the stay would be tantamount to a decision on the merits in favor of the applicants”, and so it was. The wording of Justice Scalia's short concurrence suggests heavily that the majority five had already made their minds up.
Three days later, the Supreme Court issued its final ruling on Bush v. Gore, and ended the counting once and for all, but really it had stopped on the 9th. Had the counters had the extra three days that I believe they were due, they might well have patched together a Gore majority, though it would have been illegal (due to the equal protection problems in obtaining it), it would have been interesting to see what the Court would have done by the time of oral arguments.