Theresa May is a skilled politician. She knows how to win power, and to yield power.
She is confident that the Tories will win the next election, and the one after that. In those elections, Scotland is meaningless - its single Tory MP a toothless man in a beard. Labour too is meaningless, lost in its self-flagellation.
She enjoys power, so it is no surprise that, as she announced yesterday, she will be grabbing it back from the Scottish people and our Parliament. When power returns from Brussels it will stop in Westminster, where she can control it. Scotland, Wales and Northern Ireland can go hang.
(In the process, she has also hung out Mr Mundell. He had clearly not been briefed about Theresa's speech to the Scottish Tories when, this week, he said that Scotland would have a more powerful parliament after Brexit).
Theresa knows that a week is a long time in politics. The two years since the Vow is an eternity, and anyway that was a Vow made by three men who are now, politically, dead. She is not, you may be sure, waking up at night to worry about devolution of power to Scotland.
Brexit has shone a laser light on the democratic deficit in Scotland. The Sewell convention is meaningless. The Vow was just a newspaper gimmick. And now, like it or not, Holyrood will be reduced to setting the price of parking tickets, and little else; less power than a Parish Council.
Time for Scotland to wake from the Tory nightmare, and win back its independence. Time for a new Referendum.