28/04/2015 11:51 BST | Updated 28/06/2015 06:59 BST

SNP Threats Are Just a Symptom of Britain's Endangered Constitution

While it has become evident that political polarization is damaging American society, even among some who practice it themselves, the commentator's mantra in Election 2015 has been the collapse of Britain's 'two-party' system.

But in fact political polarization is just as real in the UK as the US, and must have the same root cause: the increasing inequality caused by the uniquely severe 2008 financial crisis. For as long as even middle of the road voters are producing more at work but receiving less in their pay packets, you can expect greater demands on the State to make up the difference, and support for politicians who promise simple solutions. That, in the words of English (and American) republican Thomas Paine, is common sense.

On the surface it is producing different symptoms. The decentralized American two-party system allows candidates to go 'off message' and pander to the angry at both extremes while reinforcing the Red-Blue state divide. Meanwhile, the centralized Westminster system and preoccupation of the two main parties with marginal voters means the Greens and UKIP have emerged to mop up disgruntled English sentiment at the swollen fringes.

But in one profound sense it is having the same effect: straining to breaking point regional, political settlements that are so longstanding they are rarely even articulated. In America, the Red-Blue state divide is a scar of the US Civil War and remnant of the different notions of freedom the first immigrants brought with them; egalitarian Puritanism in the North and Royalist inspired hierarchy and laissez-faire in the South.

The enormous pressures on the British political system today also expose division and agreement that stretch back to the creation of our own Union. It is often forgotten, not least by the Scots themselves, that our countries were united by the inheritance of the English throne in 1603 by James VI of Scotland, and solidified by Scottish Parliament approval of the Union with England Act in 1707. But for another 150 years Scottish nationalism became a device in attempts to enforce Crown autocracy, just as it is being used as a wedge to engineer big government political correctness today.

So the rise of the Scottish National Party is a new aspect of a very old phenomenon, reawakened by the economic privation felt most harshly north of the border. Just as the American political battleground has reverted to the fissures present at its creation, the spectre of the English Civil War of the 1640s looms large in this twenty first century election. For if the Crown had not enlisted the support of Scottish Covenanters to crush Parliament, Cromwell's Eastern Association would not have had the support of the middling English gentry needed for victory.

The optimist should hope for a similarly galvanizing effect from the Scots nationalists today, despite their historic status as symptoms and agents of polarization. The English pessimist will vote for the UK Independence Party as an expression of countervailing nationalism. But the real patriot will choose a British political party to preserve the stability needed for economic growth, and the mother of all parliaments. She still remains our best hope for independence from greater Europe, in the world, and from self-destructive sectarianism.