Donald Trump holds up a pen to give away after signing H.J. Res. 57, which overturns a rule on school accountability standards. Credit:Bloomberg Then there's the $US1 trillion over a decade that is no longer available to fund Trump's sweeping tax cuts because of the failure last week to repeal Obamacare – and in particular, its suite of taxes that will continue to be paid by higher income earners for as long as the former president's healthcare regime operates. And under a plan drafted by House Speaker Paul Ryan – yes, the same author as for the healthcare makeover which bombed out last week – Washington would have to borrow as much as $US2.5 trillion over 10 years to pay for its proposed tax cuts. Similarly, election-time costings of Trump's tax plan estimated it would add as much as $US5 trillion to the deficit. Neither will appeal to deficit hawks in the Republican ranks. Trump, on the other hand, is banking on his sweeping tax cuts - the vast bulk of which is going to taxpayers earning $US143,000 or more - will generate economic growth and jobs – and thereby, greater tax revenue for the government. The President would collapse the current seven income tax brackets to three and reduce the corporate tax rate from 35 per cent to just 15 per cent.

Treasury Secretary Steven Mnuchin listens at right as President Donald Trump speaks during a meeting on the Federal budget last month. Credit:AP And Trump is proposing a more generous spread of tax cuts than Ryan's plan does for low and middle-income earners. On full implementation, the Trump plan would give an average income earner a cut of around $US1100 a year, compared to just $US60 a year under Ryan's plan. After ten years, 99.6 per cent of the tax relief Ryan proposed would go to the to the wealthiest 1 per cent of Americans, whereas Trump's more populist scheme would deliver about half of the total to the same group, according to analysis by the nonpartisan Tax Policy Centre. Donald Trump stands after signing four bills to nullify some education measures put in place during the Obama administration. Credit:Bloomberg Some observers say that a lesson that Trump might have learnt from last week's searing encounter with Congressional Republicans was that it could be worth reining in his own expectations if it makes victory more certain.

Stephen Moore, a Heritage Foundation economist who advised Trump during the presidential campaign, told The New York Times: "They have to have a victory here – but it's going to have to be a bit less ambitious rather than going for the big bang". A US Customs and Border Protection officer checks under the hood of a car as it waits to enter the US from Tijuana, Mexico. Funding for Trump's border wall is under threat. Credit:AP But before the cuts comes the politics. The healthcare brawl has confirmed a belief in the White House that Congress is not to be trusted. So while Trump allowed himself to be steered by Ryan and others on healthcare, a 100-strong US Treasury team is devising a detailed plan by which the administration is proposing to seize leadership in the tax debate. Treasury Secretary Steven Mnuchin is spreading the word that he is the man in the negotiation process. "We've been working diligently since the first days of this administration to develop a tax reform plan that helps achieve our goal of sustained economic growth, provides relief for middle class families and creates a more competitive business environment that supports greater job creation and reinvestment in the American economy," Treasury Department Assistant Secretary for Public Affairs Tony Sayegh said in a statement.

Some in Congress are urging the White House to take control, lest the tax debate go the same way as healthcare, because of Trump's seeming greater interest in closing a deal than in being across the detail. But Texas Republican and House Ways and Means Committee Chairman Kevin Brady is pushing back. On Sunday he told Fox News: "It wouldn't make sense to have a separate tax bill from Secretary Mnuchin, a separate one from [Trump's economics adviser] Gary Cohn, a third from whomever – why not take the basis of the House plan?". However, Brady seems not to have grasped the White House's distrust of the House Freedom Caucus, the 30-odd hardline conservatives who torpedoed the healthcare legislation. Unnamed White House sources are explaining that Trump will not negotiate with them again, and in future the President's objective would be to work with moderate Republicans and Democrats. But those White House sources were racing ahead of themselves because the administration's competing factions are yet to agree on a tax plan. As reported by Politico magazine, a "Goldman Sachs branch of the West Wing" led by Mnuchin is pitted against hardcore conservatives who are led by Trump's anarchic strategist Stephen Bannon. The Mnuchin faction is described as less ideological, more favourably disposed towards international trade deals and existing foreign relationships, and more measured in its approach to tampering with financial regulations – as opposed to the "crazier ideas coming from Bannon and the rest".

But before the administration gets to rewrite the tax code it'll likely have to weather a threatened shutdown of some of the government – Congress is required to vote by April 28 to endorse new operational funds for a slew of agencies. That's when the likes of the House Freedom Caucus, emboldened after blocking the healthcare bill, is likely to flex its muscles again, balking at keeping government open unless the new funding deal contains a rider to deny funds to the likes of Planned Parenthood. Loading Democrats likely will be uppity too. Their Senate leader Chuck Schumer has hinted at blocking funding for Trump's multibillion dollar wall on the Mexican border as his ultimate smack down for the 45th President, so they are likely to use their Senate numbers to stymie any funding bill that includes funding for the wall. It could get messy.