Not so very long ago, the job of imagining President Donald Trump’s first 100 days in office was largely the preserve of satirists.

Though much late night comedy was devoted to discussing the gold leaf that might adorn the White House, analysis of what else he might do (as opposed to what he might say) remained as thin as the policy section of the Republican candidate’s website.



But with a series of primary wins behind him and a favorable electoral map ahead, the possibility that this unpredictable populist could beat a Democratic nominee on 8 November and seize power should no longer be taken lightly.



Supreme court

The contours of the road after inauguration on 20 January have also become clearer after the death of supreme court justice Antonin Scalia, whose replacement Republicans in Congress have vowed to block until then.



Two names Trump has already floated to fill the vacancy on the bench – Bill Pryor Jr and Diane Sykes – are orthodox conservatives who are opposed to abortion and voter rights protection, and give a glimpse of what the overall court might look like if he is able to fill three further vacancies in the coming years.

Support from Senate Republicans, never mind Democrats, is far from guaranteed of course, and Trump is almost certain to spend much of the first few months in office trying to get his preferred nominee through bumpy confirmation hearings and a possible filibuster.



Vice-president

The assumption is usually that a political outsider would struggle in such circumstances, but another clue to Trump’s likely style of leadership has come amid talk of running mates for the position of vice-president in a Trump administration.

Though speculation initially focused on former Alaska governor and 2008 vice-presidential candidate Sarah Palin and has ranged as far and as wildly as Oprah Winfrey or former Republican contender Carly Fiorina, Trump himself has recently made clear he favours an experienced Washington politician to help him navigate the corridors of power.

“I would think that because of the fact that while I’m very political, I’m not a politician, I would want to choose a politician,” he told an interviewer this month in comments that could easily point to a rival such as Marco Rubio or Ted Cruz, who Trump repeatedly calls a “smart guy”.



For his part Cruz, like many critics, suggests that much about a Trump administration remains inherently unknowable – despite his eye-popping campaign promises to ban Muslims, deport immigrants and erect a wall with Mexico.



“The truth is that if Donald Trump became president nobody knows what the heck he would do,” claimed Cruz after heavy defeat in Nevada on Tuesday. “He doesn’t know what the heck he would do.”

But just as Republicans are having to think the unthinkable about their likely presidential nominee, politicians of all stripes may have to adjust to a radically altered notion of what counts as far-fetched if Trump wins.

One example is the speed with which previous sceptics might swing behind Trump once they realise that his campaign represents an anti-establishment wave to match, or exceed, that of the Tea Party. Despite him being shunned by lawmakers until now, the first two members of the House of Representatives came out to endorse Trump this week.

Democrats are hopeful that having Trump at the top of the ticket in November may increase their chances of seizing back control of the Senate. Yet if the balance of power remains as it is now, Trump could have enough support in Congress to quickly enact some of his less contentious ideas in a brief honeymoon phase.

The wall

These might include increased funding for the US military and his proposal to strengthen the southern border with a continuous wall, even if getting the Mexicans to pay for it may have to wait for fraught bilateral negotiations that are harder to imagine bearing fruit.

Whether a more extreme immigration and foreign policy would ever clear a 60-vote hurdle in the Senate is another matter of course, but Democrats could quickly find the tables are turned on them over the question of executive action.

Faced with opposition from Republicans on Capitol Hill, Barack Obama has increasingly used his constitutional (and some would argue, unconstitutional) prerogatives as president to make progress on a host of contentious issues.

Some of these, a President Trump would be able to reverse just as quickly because they continue to rest only on executive action for legitimacy rather harder-to-reverse acts of legislation.

Guantánamo

Obama’s long-delayed plans to close Guantánamo Bay for example – first announced during his initial 100 days in office – could be easily reversed by Trump, who wishes to “load it up with bad dudes”. “Gitmo, we’re keeping that open,” he said after winning the Nevada caucuses on Tuesday night.

Though Trump mysteriously wants the Cubans to pay for that too, at least his opposition to Obama’s executive actions toward rapprochement with Havana is less fierce than his promise to rip up the nuclear treaty with Iran and recommence sanction negotiations there – with or without international allies.



Immigration

Much of Obama’s immigration plan, which is already under review by the supreme court, could not only be reversed on day one by Trump, but driven hard in the opposite direction.



This is particularly alarming for immigrant rights groups because Obama has leaned heavily on the concept of prosecutorial discretion to justify his plan to shield undocumented immigrants from the threat of deportation.

Since Trump has argued that virtually all the estimated 14 million people in this category should be subject to the full force of the law, it may prove legally hard to block mass deportations. Even if the practical, humanitarian and political impediments remain unthinkably high, the insecurity felt by millions already living in the legal shadows would be real the moment Trump wins.

Syria

President Trump is likely to be forced to proceed more slowly on other aspects of foreign policy. Despite his bluster about making America win again, Trump has been lukewarm on the question of unilateral intervention in the Middle East and shown sympathy toward Russia’s Vladimir Putin, who may be left alone to reorder Syria to his own liking.

Other promises to tackle the Islamic State and terrorism may prove similarly complicated by the introduction of reality into the conversation. A temporary ban on Muslims entering the United States, for example, may prove impossible to sustain from legal challenge – even with a more Trump-friendly supreme court.

China

The centrepiece of Trump’s economic agenda, trade, is an area where change could be felt quickly or slowly depending on how much Obama achieves in his last year in office.

A massive trade deal with Asia is nearing completion and has already cleared the highest hurdles in Congress, but would instantly be in jeopardy if the ink is not dry in time.

Renegotiating trade terms with China – perhaps the the trademark of Trumpism – may be a longer run thing, with no guarantee that Beijing would agree or that Congress would ratify any fundamental rewriting of terms.

Perhaps the biggest changes would come simply through the signal that a Trump presidency sends the outside world about the future direction of US policy.

A collapse in the value of the dollar on the day after November’s election, for example, would give Trump the ability to claim (perhaps unconvincingly) that he was already doing his bit to tackle China’s currency manipulation.

Otherwise so much of what Trump stands for is about attitude rather than instant action. “Make America Great Again” is a slogan not a manifesto, and one that the candidate claims he can bring about through a series of savvy deals and business acumen rather than any single concrete policy.

The wheeling and dealing would no doubt begin on day one but may take more than 100 days for anyone, including Trump, to assess.