Corbyn understands foreign policy – he proved it yesterday with Russia and he's proven it in the past

The very worst foreign policy mistakes have been made when the front benches of both parties agreed to stand together: the Commons voted for Invading Iraq in the same spirit of non-partisan ‘unity’ against external enemies. Both decisions were vigorously backed by Chris Leslie and IDS. Both were opposed by Corbyn

Iain Duncan Smith said Corbyn shouldn’t “Play politics” over the poisoning by talking about Russia-linked donations to our governing party. The Tory backbenches roared “shame” and “disgrace”. Chris Leslie MP, prominent member of the dwindling New Labour “Resistance” to Corbyn declared it is "just not appropriate" to push "party political differences" when "our country is potentially under attack" in response to the Labour leader’s comments in the Commons last night.

Liberal commentators, New Labour holdouts and angry Tories all want politics kept out of the House of Commons when security matters are debated.

But politics are key to how we respond to the Salisbury nerve gas attack. If the Russian government did back attempted murder on British soil, the UK needs to make a firm response. Far from being “misjudged”, Corbyn pointed to one of the most effective responses we can make. He pointed to what the Russians want from us, and what we can do about it.

Broadly speaking, the Russian oligarchs made their money from the “Wild East” privatisations during the economic “shock treatment” of the 1990s. Putin’s rule rests on reining in those oligarchs, befriending some, imprisoning others. Being rich in Russia now means being friendly with Putin. The Russian leaders’ business friends like the UK: they want to trade – and clean – their money in the City, invest it in London property and send their kids to British public schools. They often want to keep open options to follow their money to the UK in case they fall out with Putin.

Financial sanctions on Putin-friendly Russians, including seizing cash and assets in the UK could be a powerful weapon, but one that is regularly ruled out. This was made explicit in 2014 when deputy national security adviser Hugh Powell was photographed entering Number 10 with a document listing options for responses to Russia’s Ukraine invasion. Powell’s slip-up exposed UK policy would not jeopardise City cash. Powell’s document said Britain would “Not support, for now, trade sanctions … or close London's financial centre to Russians.”

City interests, the luxury property lobby and Russia-linked investors have a real interest in resisting sanctions powers. These groups are also among the Tories top funders. May will have to run against Tory donors’ interests to make a serious stand against Putin.

Far from “playing politics”, Corbyn was pressing this precise point. After telling Parliament this was a “deeply alarming attack” which “the whole House condemns” Corby referred to “huge fortunes, often acquired in the most dubious circumstances in Russia and sometimes connected with criminal elements, have ended up sheltering in London and trying to buy political influence in British party politics.”

Corbyn called on the government to “introduce new financial sanctions powers”. This isn’t a vague gesture, it is a concrete call. May’s government are “currently resisting Labour’s amendments to the Sanctions and Anti-Money Laundering Bill that could introduce the so-called Magnitsky powers”. Sergei Magnitsky was an anti-corruption investigator who died after being assaulted in a Russian prison in 2009. In response, the US Magnitsky Act creates powerful sanctions powers. Labour want similar powers here.

Corbyn was calling for specific powers, and pressuring May to introduce them. There is a good chance that the government will be forced to concede. While backbenchers like Chris Leslie or John Woodcock or Yvette Cooper make “solemn” and “cross party” noises, Corbyn has actually, by acting like an opposition, begun to shift policy.

The call to not “play politics” is particularly hypocritical given Conservative MPs, Ministers and the Tory press spent weeks playing politics with an absurd and entirely fake story about Corbyn-the-Czech-spy. They played that silly game up to the point one MP was forced into a humiliating public apology. By contrast Corbyn is shocking faint hearted pundits by calling for actual policy changes.

There is a regular call to suspending politics for the sake of empty displays of unity, but it usually gets us into a bad place: the very worst foreign policy mistakes have been made when the front benches of both parties agreed to stand together in Pound Shop Churchill poses: the Commons voted for Invading Iraq and bombing Libya in the same spirit of non-partisan “unity” against external enemies: both decisions were vigorously backed by Chris Leslie and IDS. Both were opposed by Corbyn. Both interventions did nothing for “security”, instead spreading chaos and misery.

Corbyn talking about actual politics inside the Houses of Parliament makes some of the political class feel “uncomfortable”. Because real political change is outside their comfort zone. But this is how change happens.