(Magna Carta was not what you thought, exactly, and Paine is right – the broad impression gained from reading the text is disappointing and sectarian in favour of the narrow interests of the “Barons”. But it’s the symbolic act of limiting State Power as a principle, that mattered.)
We were the first to arrive at some approximation of real individual liberty, and we may be the first to lose it utterly having just gained a semblance of it. But we have a good record overall, to be proud of as a people: we tried to export it before the Sartres and Marcuses and Gramscis and Hobbsbawms got to it and rotted it. We ought not to weep: for others will come after us to battle on for liberty, some day, knowing what we tried to do.
We succeeded, better and better over nearly 800 years: a grand record considered on the broad sweep of human history.
I guess we are like that medieval madman in all the movies, who nearly got to the top of the scaling-ladder, in the face of rocks, boiling oil, swords and the like, and fell off backwards with a bolt through his chest, three yards from the battlement. Oh well, never mind.