We knew from the moment USC lost at Oregon State, that the Trojans’ had a very hard road ahead of them — almost certainly an impassible road ahead of them — to get to the BCS title game. And we wrote that, the night of Sept. 25.

They had to win out and hope all but one team above them lost. And most of those teams had to lose twice because a one-loss team out of the pitiably weak Pac-10 wasn’t going to jump a one-loss team out of the Big 12 or SEC.

USC got some help. But not enough. And now it’s over, except for the voting.

Here’s why:

Alabama 36, Auburn 0 … Texas Tech 35, Baylor 28 … Florida 45, Florida State 14.

Stick a fork in the Trojans’ national-title hopes. Turns out that, yes, this is the one year — the first since Pete Carroll arrived, anyway — that they couldn’t afford even one defeat in the Pac-10.

No combination of results in the few remaining games can get USC to No. 1 now.

Those three scores, above, finished them off for No. 1, which always is the goal, at Troy.

Alabama and Florida winning sets up a huge SEC title game between the two. The unbeaten Tide vs. once-beaten Florida, and the winner of that game is going to the BCS title game, guaranteed. Florida’s one defeat was in the SEC, which clearly is far better than the Pac-10. Especially this year. No way USC climbs past the winner of this game. Not gonna happen.

Had Alabama and Florida each lost to their arch-rivals today, and then Florida had beaten Alabama in the SEC title game — leaving both teams with two defeats, USC probably (but not certainly) would have climbed over both two-defeat teams. Though SEC enthusiasts could have made a strong case that a two-defeat SEC team is better than a one-defeat USC team, given the schedules they all played.

Also, Texas Tech winning creates a scenario in which it is impossible for either Texas or Oklahoma to come out of the the Big 12 with more than one defeat. Not to mention Texas Tech is 11-1, too, and the Red Raiders also might climb over the Trojans if they can get to 12-1.

The real issue is Texas and Oklahoma, ranked Nos. 2-3.

Even if Oklahoma loses to Oklahoma State tonight, which could happen, Texas will be 11-1 — and will stay 11-1, because an Oklahoma defeat puts Texas Tech in the Big 12 title game. And no way does USC go past an 11-1 Texas.

But what if Texas goes to the Big 12 title game and somehow loses to 9-3 Missouri? That can only happen if Oklahoma wins, forcing a three-way tie that Texas wins (and goes to the Big 12 title game) by virtue of being hirer-ranked in the BCS poll on Sunday.
Meaning Oklahoma would sit out the Big 12 title game and be 11-1 — and certain to go to the BCS title game ahead of the Trojans if Texas lost to Missouri.

Of course, all these “if this, if that” scenarios assume USC defeats Notre Dame and UCLA, which isn’t a certainty, given that their perennial goal is now unachievable. These guys could be flat tonight, and next Saturday.

And now it gets worse.

If Oregon State wins today, it would go to the Rose Bowl by dint of its head-to-head victory over USC. And USC would get to go to something like the Fiesta Bowl and play a top-five team and, if the Trojans won, have a chance to do a lot of deep sighing and a little whining about how Mike Garrett thought he had a tough schedule lined up.

But at the moment I posted this, Oregon is leading Oregon State 23-10, and an Oregon victory gives USC the Pac-10 title outright, which ties the Trojans to the Rose Bowl … where they get (zzzz) Penn State. Meaning they are stuck with the equally as discredited Big Ten in their bowl game instead of a chance to go to a bowl where they could play one of the Big 12/SEC heavyweights and show how good they think they are.

Yes, it would be better for USC to share the Pac-10 title. But not even that is working out.

Really, we can’t feel too sorry for the Trojans. It was in their control. If they won at Oregon State, they could have been unbeaten and playing for the national title — because unbeaten USC gets to go, even out of a weak conference. But one loss? Nope. Done. Because the team they lost to, Oregon State, itself lost 36-28 to Stanford (!), 45-14 to Penn State and 31-28 to Utah.

It always was going to be hard, from the moment the clock hit 00:00 at Corvallis. Already, a batch of really damaging Pac-10 defeats were in the books, and USC’s schedule didn’t look tough enough. It needed help. Lots and lots of help. It got some, but not enough, and now it’s going to finish as maybe the No. 4 team in the country (assuming it wins out), which is great, in most places, but not the intent of this team which, arguably, was one of the best of Carroll’s tenure.

Except for one night. One night in Corvallis that the Trojans never could expunge from their record.