There is no rhyme or reason to the obduracy of Theresa May. She has chosen the hardest, take-no-prisoners Brexit, and that will probably be her epitaph. In the Lords this week, in one excoriating speech after another, the irrationality of May’s trajectory was spelled out in forensic, lordly style. Ice queen perched on the steps, she cast her refrigerator glare upon them as one peer after another rose to modify her plan to put Britain in the freezer.

The queen of this Narnia ordains that she alone is keeper of the sacred “will of the people”. End of. Any slight deviation from her personal interpretation of Brexit is a betrayal of democracy itself, and no one else has any right to suggest alterative exit routes or timetables.

This preposterous seizure of absolute power over the country’s most important decision was knocked back only slightly by the judges, those “enemies of the people”, insisting parliament should have the right to debate it before she presses the trigger. Parliament itself is in the process of abrogating its rights by allowing the prime minister to refuse all amendments.

None of the serious amendments in the Lords are wreckers. None suggest blocking Brexit. All concern ways to leave with least damage. There is great public support for allowing EU citizens here already to stay – so why not open negotiations with that signal of continuing close neighbourliness? Today’s figures suggest EU citizens taking flight already.

Her refusal to give parliament a meaningful vote on whatever deal, or no deal, she emerges with in two years’ time is a constitutional shocker. Only the certainty of the Daily Mail and Rupert Murdoch acting as her rottweiler guard dogs gives her the nerve to grasp for herself such unconscionable absolute power.

On Northern Ireland, a cross-party amendment calls to guarantee an open border, as peer after peer warned about the very real danger to the peace process of a new hard border. Her refusal is an affront, reconfirming Northern Ireland’s sense of its neglect in the union.

She might have a plausible point – though not one I agree with – in rejecting an amendment to keep “free and unfettered access to the single market” as a curb on her negotiating hand. But none of the other above amendments deny “the will of the people”. May could easily accept all three with good grace – but that is the quality we now know she absolutely lacks.

Instead she has decreed any amendment a defiance of the people, just because she can, because her own non-Brextremist MPs are cowed, while Labour has abdicated all opposition. The fear of being thought “anti-people” paralyses them all. The Lords’ wise amendments are wasted breath, when they pre-agreed that even if May rejects every one, they will not press for compromise in a ping-pong between the two houses: they will lie down like sheep.

May ordains any delay to her own arbitrary timetable is a denial of “the people”. But if she accepted those amendments, there would be no delay. Besides, there is very good reason to hold back until we know who we are negotiating with after French and German elections: the EU on the other side of the table is volatile and may change radically. That’s not a remainer’s foot-dragging tactic – it’s common sense.

Bar the Lib Dems, most in both Houses think Brexit inevitable: only Brexiteeer propaganda pretends “remoaners” are seeking to prevent it.

May’s refusal to tolerate even these amendments suggests what an alarmingly bad negotiatior she will be in Brussels. Already her haughty approach, surrounded by her mastiffs, is prompting ominously bared teeth on the EU side.

Think how differently someone subtler might have approached this phenomenally difficult task, setting out eager for good relations with warmth and amity, careful not to needlessly provoke. Threatening to turn Britain into an offshore tax haven has raised every hackle among the other 27. Nor was there any need to mark immigration as her top red line: in such a complex, multifaceted deal, she has damaged her own negotiating position.

As the Guardian has been analysing all week, the prospects for a good outcome look pretty grim. In the turbulence of the next two years, with the chance of a bad deal/no deal, the economy here may stumble. Higher food and fuel prices, with buying power of pay packets still 4% below 2008, may see public attitudes shift markedly.

Kenneth Clarke may be right when he predicts that in a few years’ time there will be surprisingly few who recall personally voting for Brexit: he has experience of voter amnesia. The Brexiteers will frantically try to blame filthy foreigners for enacting revenge, but Theresa May can expect little gratitude if she fails to bring home the bacon. Taking this hard stand against all comers, resisting the backing of parliamentary approval, she takes all blame on herself – and it may do for her.

The Lords will vote on amendments next week. May has no incentive to compromise, as Labour and others say they will vote for the unamended bill anyway. If the Lords dares not press moderate amendments to this most vital bill, what’s the point of all those good speeches from so many knowledgeable peers?

Once Jeremy Corbyn proclaimed Labour would vote for the bill whatever, he sold the pass. No surprise, from a leader who at every turn has barely disguised his age-old antipathy to the EU.

The second chamber stands as a restraining check and balance to dictatorship by majorities – and on Brexit, that was a slender majority indeed. May’s frosty glare warned them they could be abolished if they insist on even moderate amendments to her will. But if fear for their own survival stops them carrying out their duty, they risk rendering themselves pointless anyway. The will of the people is not expressed in a 130-word bill. The will of Theresa May could yet be broken by her own imperialism.