Politics is mathematical. Like the Torah, each word has a numerical value. 'Immigration' gets at least ten points - usually more. 'Blunder' gets seven. 'Immigration blunder' is therefore 17 points. If you construct it appropriately, you can add the phrases 'foreign criminals' (15 points) and 'terror suspects' (25 points), as so: "The immigration blunder saw biometric data left unchecked, meaning tens of thousands of illegal immigrants - as well as terror suspects - could have been permitted entry into the UK."
Note the way you can therefore get an immense 57 points from the row engulfing Theresa May this week. Ed Miliband duly made the choice of devoting all his questions to it.
I doubt he'd had time to read the Metro. On its front page today, it featured the story of army veteran and his wife driven to suicide by destitution. Sick of trying to live on £57.50 and the six-mile daily walk to the soup kitchen, their bodies were found at their home in Bedworth, Warwickshire, last week.
There's no maths for that but it's the sort of thing great opposition comes from - state of the nation stuff. Tony Blair did it with James Bulger. David Cameron did it with Fiona Pilkington, the woman who killed herself and her daughter after years of bullying and intimidation on their council estate.
Instead, we suffered a tiresome trawl through the immigration debacle, as Miliband asked question after question like a child putting together bric-a-bracs without any deftness and then expressing surprise when they all fall down. There was much mock outrage and stabbing hand gestures, all of it failing to land the slightest blow. By his last question Miliband had retreated to saying the prime minister was "out of touch" - his default attack.
"He's completely lost his way," Cameron said dismissively, entirely untroubled, happily defying the laws of political calculus. To his side, Theresa May was dressed in resplendent white, as she couldn't possibly do any harm to anything. George Osborne kept whispering cruelties into her ear about the benches in front of them and sneering wetly when confronted by views other than his own.
Politics as mathematics, but the sums came out all wrong. Ed should have gone for something he actually believed in.