BUT is independence what the Scottish people — as opposed to the S.N.P. — really want? In spite of the recent political fireworks, Scotland is a deeply conservative country (with a small “c”: the Conservative Party itself has been reduced to a tiny rump). And for the last 40 years or so, the preference of the Scots has hardly changed: most want Scotland to take charge of its own affairs as other small nations do while, if possible, staying in the United Kingdom. Their general view of devolution follows logically: A Parliament isn’t worth much if it can’t change the lives of ordinary people — if it doesn’t have full control of the economy.

And yet no party is offering the Scots that middle course. Though the Cameron coalition government is still split on how to run a Unionist “no” campaign in the referendum, Mr. Cameron himself boldly declares that there can be no question of giving Scotland control of its own finances — which plays straight into the S.N.P.’s hands. If the only way for Scottish voters to win that full self-government is through independence, then many of them, however reluctantly, may vote to leave the union.

Only in recent weeks has a campaign for that second question begun to emerge: Future of Scotland, which wants the referendum to offer not only a yes-or-no question on independence but also something along the lines of, “Do you want full self-government for Scotland (so-called devo-max) short of independence, leaving only foreign affairs and defense to the United Kingdom?”

The group is still getting off the ground; its first rally won’t take place until next week, in Glasgow. But its backers insist they are voicing the wish of the largest single bloc of Scottish opinion. Indeed, it has already attracted powerful social lobbies: the trade unions, the churches, the council of voluntary organizations. In Scotland these are big players who provided the muscle behind the successful campaign for a Scottish Parliament.

The Unionist camp is utterly opposed to any second question, but Mr. Salmond is relaxed about it. He knows that the step from that sort of “federal” autonomy to complete independence is a short one.

To help make that step even easier, Mr. Salmond promotes an uncannily cool version of sovereignty: call it “independence lite.” He would keep the queen as monarch and retain the pound as currency. There would be no customs or passports at the border. And the “social union” of family and business bonds that tie the English and the Scots together so intimately would stay intact.

Which doesn’t mean things wouldn’t change. An independent Scotland, Mr. Salmond claims, would be a “fairer” society than England. Mr. Salmond enrages Labour by promising that Scotland will become “a beacon for progressive opinion.” The Scottish National Party, once seen as right-wing and romantic, has made a steady leftward transition to social democracy since it began to gather support. Now, ironically enough, it can be seen as the most “British” of parties: since 2007, successive S.N.P. governments have fought to preserve what remains of Britain’s postwar welfare state.