The risk for conservatives is moderate Republican voters disgusted by Trump stay home on polling day.

The mogul's base of hardline grassroot voters could act on his persistent lashing of House leader Paul Ryan and veteran Senator John McCain by not supporting Republican congressional candidates.

Hence, Democrats are a slightly better than a 50 per cent chance of picking up the net four seats to wrestle control back of the Senate, assuming Clinton's would-be vice-president Tim Kaine breaks any 50-50 deadlock in the 100-seat chamber.

Make-up of Congress

Trump's crash had suddenly made it plausible for Democrats to achieve a once unimaginable landslide to collect the net 30 House seats to take full control of Congress.

Republican House Speaker Paul Ryan will not defend or campaign for Trump. Andrew Harnik

If a Democratic clean sweep occurs, Wall Street would be spooked by extra taxes on business and the wealthy, a higher minimum wage, more employee family leave, free university, new financial regulation, pharmaceutical price controls and a crack down on oil and gas drilling.

However, Democratic dominance is not the base case. Blatant gerrymandering of House district geographic boundaries and sparsely populated rural regions conservative Republicans control make it hard for Democrats to win.


Charles Gabriel, president of Washington-based political forecasting firm Capital Alpha, says such deep conservative districts that are like "virtual man caves".

Most likely Clinton will face a Congress where she needs to negotiate with Republicans.

Americans and the political parties are far more ideologically divided than when Bill Clinton governed. So achieving compromise will be awfully difficult, as President Barack Obama knows only too well.

Taking a half glass full view, Clinton will be more effective than Obama at wooing foes across the aisle.

House of cards

Veteran political analyst Charlie Cook says it's been "very, very hard" to get Obama to meet or pick up the phone to congressional Democrats, let alone Republicans.

As a senator for eight years, Clinton effectively courted Republicans to pass legislation. She has referred to McCain as her "favourite" senator.

However, the senate is not where a president Clinton's major problem will lie.


Ryan's House of horrors will be unruly.

If, as generally anticipated, the 59-seat Republican majority is roughly cut in half, Ryan will likely lose more reasonably-minded Republicans from urban areas.

He will have a terrible challenge unifying his disparate caucus that includes Tea Party elements, the Freedom Caucus and Trump loyalists. Like Trump, they may blame Ryan for the election loss.

The power of the renegade populists would rise, as they represent a larger share of the Republican House majority.

"If Paul Ryan's majority in the House gets cut in half, that really lowers his margin for error," election analyst David Wasserman says.

Potential shutdown

A government shutdown and threat of sovereign debt default could return in 2017.

To lift the government's debt ceiling Ryan may need to outrage hardliners and break the party's so-called Hastert Rule.


The "majority of the majority" informal governing principle curtails minority Democrats tabling legislative bills for a vote on the House floor.

So besides the president, assuming Ryan remains House leader, the 46-year-old will be the most important political figure in US politics from 2017.

It is why Ambassador to the US, Joe Hockey, brokered a meeting for Prime Minister Malcolm Turnbull to meet Ryan on Capital Hill last month.

Ryan, a vice-presidential running mate of Mitt Romney in 2012, is widely seen as a potential 2020 presidential candidate.

Rebuilding the Republicans

Before then he will face the arduous task of rebuilding, redefining and uniting the Republican Party in wake of its failed Trump experiment.

How he manages his own fractured caucus will largely determine Clinton's legislative capacity.

Beyond foreign policy, senior personnel appointments and limited other presidential powers she can implement without legislation, Clinton will need to cut deals with Ryan.


Firing a warning shot Friday, Ryan accused Clinton of being "arrogant, condescending and paternalistic" in her belief in big government.

He is a tax cutting, small-government believer in supply-side economics. Clinton argues against such "trickle down" economics.

A Republican-friendly corporate tax reform mixed with Democratic-supported infrastructure investment offers the best compromise opportunity.

Yet it won't be easy. Most Democrats hate the idea of lowering the corporate tax rate. Republicans generally oppose spending more taxpayer money on public roads, rail and airports.

Elsewhere there are slim pickings for deals.

Hence, there is a general glumness in Washington about the prospect for ending the past six years of gridlock. Partisan paralysis could stymie Clinton, just as it did Obama.

John Kehoe is US Correspondent for The Australian Financial Review in Washington