Donald Trump's economic deal with the devil has failed even in its most immediate and cynical objective. It is downhill on every front from now on. The president debased the US public accounts with a Peronist fiscal policy of staggering irresponsibility in order to keep control of Congress - or rather to buy Congress with $US1.5 trillion ($2.1 trillion) of future public debt, might be a better description.

Donald Trump is loading up on public debt. Credit:AP

He lost the House anyway, and with it his chances of avoiding a blizzard of subpoenas from the oversight and intelligence committees. The Democrats won the popular vote by 7 per cent at the absolute apogee of a Republican fiscal boom.

The sugar rush of stimulus so late in the economic cycle is already starting to fade. Over the course of 2019 the Faustian pact will progressively close in on Mr Trump, and on the credit-rating of the US Treasury. Morgan Stanley said it will turn ineluctably into "fiscal drag" as the months pass without more handouts to feed the monster.

Perhaps Speaker Nancy Pelosi will give Trump a partial reprieve. Common ground exists on infrastructure spending. But the Democrats will keep him on a tight leash before the next election. "They are not going to give him anything to run on, any victories," said Steve Blitz from TS Lombard.