Democrats facing 'chaotic government' with no Trump and no policies

US policy-making will be "chaotic" over the next term given Democrats have "run their campaign largely on the basis of Trump Derangement Syndrome", says former NSW Treasurer Michael Costa.

Mr Costa predicted factions within the Democratic Party would likely begin to turn on themselves without the unifying presence of President Trump.

"The glue that's held their party together has been Trump derangement and that's about to end," he said.

"Their left-wing is setting the political agenda and the right-wing is so Trump-deranged, it's allowed them to run with it.

"I have very little hope we're going to get a sound policy agenda."