The high line stopped being a bluff, and that is the problem

Semi-automated offside took the doubt out of the trap, and back fours have quietly started stepping up a little less.

The offside trap was never really about the rule. It was about the assistant's flag going up because he thought he saw something. A back four would step, all four together, and the striker would find himself two yards clear with a raised flag behind him and no idea whether he had actually been level. That uncertainty was the weapon. Not the line.

Now a computer knows. It knows to the centimetre where the shoulder was at the exact frame the passer's foot met the ball, and it will tell you three minutes later with a little animation. Which is fairer. Nobody sensible argues otherwise. But look at what it did to the risk calculation for a centre-back standing on the halfway line.

Before, stepping up was a coin flip weighted in your favour. Marginal calls went the defender's way often enough that a well-drilled line was worth the occasional goal against. Now a marginal call is not marginal. It is a fact, and if the fact says the striker's knee was behind your hip, the goal stands and you have conceded from your own halfway line with the keeper stranded on the edge of the D. Same action, worse expected outcome.

Watch the good sides now and you see the adjustment rather than hear anyone announce it. The line sits a couple of yards deeper than it did five years ago in transition moments, and the trigger to step has moved from the pass being played to the passer's hips turning. Defenders step when the ball carrier is forced onto his weaker side, not when he simply looks up. It is a slower, more conditional trap.

The knock-on is a compression problem. Drop the line two yards and the space between the last defender and the deepest midfielder grows, because midfielders do not drop in sympathy, they are chasing the ball. So you get the modern picture of a broken team: a well-organised back five, and a midfield twelve yards up the pitch from them with a lovely receiving pocket in between for anyone clever enough to stand still in it.

I would rather watch the old version. Chaotic, occasionally unjust, but it forced strikers to time runs instead of loitering on the shoulder and waiting for the technology to sort it out. Precision fixed an injustice and cost us a skill. That trade happens more often in football than anyone admits.