Jonny Steele, it seems, received the ball in an offside position, just before Cahill slotted home the game-tying goal.
Of course, this was discovered well after the goal was actually scored. No one pointed out Steele's position on the broadcast, there was no booing when he got the ball and no defenders were raising imaginary flags in an attempt to get the linesman's attention. That Steele was a whisker offside didn't register at the time to anyone.
It's clearly a close call. One that assistant referee Craig Lowry missed, right?
If the assistant referee, properly positioned and attentive, is in doubt as to either an offside position or involvement in active play, no offside signal should be given. However, assistant referees must be properly positioned, focused, and attentive at all times so as to fulfill their obligation to assist the referee with this critical decision.
It's more than possible Lowry, an official with 16 years experience, was in position, but wasn't absolutely convinced of Steele's offside position and played the advantage. Like he should have. It's cold comfort for Sounders fans, sure (and something of a loophole for us Red Bulls fans) but it's a perfectly valid explanation for what happened Sunday night.
Furthermore, the first pass wasn't the one that lead to the goal. The Sounders missed several tackles that could've killed the Red Bulls' attack.
If anything, Steele's positioning is revisionist history (Ctrl+F "offside" on any of those pages). Nearly everyone missed it until hours later. It stings to drop points in a game you, or your team, were heavily favored to win, so we get excuses like Steele's position.
Of course, this is going to be juxtaposed against the late offside call against Robbie Keane, which seems comparable, until you realize Keane, even with a bad camera angle, was well past the last defender when he scored a potential equalizer. The play Cahill ended up scoring on was much, much closer. And with far more opportunities to kill it.