Angus Taylor's budget reply shows times have changed since Peter Dutton

"Change or die."

That was Angus Taylor's self-imposed remit for the Liberal Party he stepped up to lead just three months ago.

Last night, he chose change. In political terms, of course, he still might die. But he won't die wondering.

Budget reply speeches from a first-term opposition leader are usually comfort food. Sort of rhetorical pizzas; heavy on the carbs of ideological scorn, cheesily oozing with tribal outrage, and noticeably short on the protein of actual things the opposition would do differently.

For comparison, just three years ago Peter Dutton's first budget reply speech entailed 30 minutes of fist-shaking at Labor's budgetary profligacy, climate policy and broken promises, plus a rewarmed promise to let Australians raid their super for house deposits, plus a promise to restore $50 million in funding to protect Australia's multicultural communities from abuse. That was it: a pouffy dough-ball, dotted with shavings of last year's budgetary ham.

But last night, Taylor went for something completely different: Meat Lovers. Extra large. Hold the base.

Who do you discretionary trust?

Not only did Taylor commit his party to opposing Labor's changes to negative gearing, capital gains tax and the tax treatment of discretionary trusts in the parliament, he also committed to repealing them in their entirety at the first opportunity.

This itself is significant enough. The changes to taxation of trusts, for instance, are not due to take effect until July 2028. At which point, if the three-year election cycle runs in an orthodox way, the nation could well be in the middle of an election campaign. In which Taylor — whose own asset portfolio was described by the Sydney Morning Herald as "opaque and labyrinthine" owing to his extensive use of family trusts — would be obliged to defend tax minimisation to the death.

"Who Do You Discretionary Trust?" You can picture the campaign lines now.

But there's more.

Taylor last night became the first Liberal leader since Malcolm Fraser to promise the full indexation of tax thresholds, eliminating the phenomenon of bracket creep.

This is where inflation and wage rises push taxpayers into a higher tax bracket, obliging them to pay more tax, even though the basic balance between what they earn and what they spend hasn't changed.

What treasurers theatrically announce from time to time as "tax cuts" are commonly just readjustments of bracket creep, dressed up as a present; it's like if a landlord who has written an automatic annual rent increase into your lease pops around every Christmas and performatively gives you a lovely pot plant.

Make no mistake, what Taylor has announced here is a very significant measure, which blows up a heretofore fairly quiet sweetheart deal between the two major parties. Nobody wants to index income tax rates, because they're addicted to the campaign press releases announcing tax cuts.

This change, Taylor says, will "force government to respect your money".

It would also cost the budget more than $20 billion over the next four years, and that's before factoring in the additional revenue Taylor would forego by reversing the changes on negative gearing, capital gains tax and trusts.

Two major gambles

This is his first big gamble: an economic one.

His second is a cultural one: a full-throated broadside at Australia's immigrant community.

Taylor, who in recent weeks has floated the view that Australia shouldn't take newcomers from "bad countries", has now explicitly linked Australia's housing crisis to immigrants.

The net immigration figure in a Taylor government, he announced, would be set according to how many houses we've built as a nation in any given year.

Plus, he said, new immigrants under a Taylor government would be largely barred from Australia's welfare safety net — from 17 separate programmes from Job Seeker to the NDIS — until they achieved citizenship status.

To members of Australia's large Indian and Chinese diaspora, for whom taking on Australian citizenship means renouncing citizenship of their birth country, Taylor's message was sanguine: "You need to make a choice."

An extraordinary week in politics

This week has truly been an extraordinary one. It will go down in Australian history as the week in which the two-party system finally began to crack open in response to the steady and cumulative abandonment by voters this century of major parties for other options, be they teal or One Nation.

This week, the Labor Party and the Liberal Party each selected for destruction a policy position on which they had together for decades largely maintained a collusive silence.

The Labor Party stopped pretending that decades of tax breaks for investors and cash giveaways to first home buyers hadn't played a significant role in the vaulting unaffordability of housing in this country.

And the Liberal Party has promised to stop the "big steal" of bracket creep, while for good measure abandoning the historically bipartisan view that immigration is a source of growth and wealth for this country.

We live in turbulent times. Attention is short.

Which is why Taylor's campaign slogans — taken for a run around the block last night for the first time — are short and simple.

"Axe toxic taxes. End Labor immigration. End net zero."

Is this the same net zero to which Taylor as energy minister personally committed the Coalition just five years ago? Yes, it is. But attention is short. And times have changed.

To appreciate just how much they've changed — even in the Liberal Party — it's worth one more look at that first budget reply speech from Dutton, considered at the time a hardliner on immigration. Apart from using the speech to promise $50 million in security cameras and measures to keep diverse communities safe, Dutton uttered the following words:

"As the Minister for Border Protection, I made tough decisions to keep our borders secure. But I also brought in record numbers of people from India, China and many other countries."

Three years ago. Feels like a hundred.