1) Unite the American public behind his controversial presidency or at least gain legitimacy
While there has rarely if ever been a candidate who so starkly divided opinion, there are a couple of adjectives we can all agree upon. Donald Trump is unique on both a personal and political level and pretty much everything since he declared his run for the presidency has been unprecedented. Both terms apply to today's inauguration and the many challenges that lie ahead.
There has certainly never been a less popular incoming president, nor an inauguration so overshadowed by protest. In stark contrast to the mood music of President Obama's signing in eight years ago, the rest of the world will see a bitterly divided USA and a new leader with very little legitimacy.
Historically unpopular throughout, losing the popular vote was never going to help Trump win over his critics and the lingering belief that his victory was a result of Russian interference has reinforced that sense of illegitimacy. A chaotic transition process and period, characterised by controversial appointments, a running war with the media and yet more bizarre tweets, has made matters worse.
Apart from his victory speech, Trump has made very little attempt to be magnanimous or reach out to opponents. Doing so in today's acceptance speech is absolutely imperative. Gaining power merely requires winning more votes than your opponent. Wielding it effectively demands taking people with you. Without building at least a degree of consensus and unity, Trump will struggle to achieve anything in office.
The Sportsbook market on what he will say first in the speech as 'Make America Great again' as strong favourite.
2) The new administration must swiftly demonstrate competence to quell fears of amateurishness
Arguably Trump's biggest selling point was his total lack of political experience. Now he has to govern, it could become his achilles heel. We are yet to see any evidence that the new president has coherent policies or even the ability to construct a team capable of governing. Only 29 out of 660 appointments have been made.
Of those that have, Trump's picks are almost all controversial. One Cabinet pick after another has endured tough confirmation hearings, revealing an alarming lack of basic policy knowledge. The likes of Betsy DeVos, Tom Price and Rex Tillerson will continue to face deep scrutiny of potential conflicts of interest. We don't know if any of these characters have either the resilience or defence to survive the brutal environment of US politics.
A chaotic campaign made for entertainment. A chaotic transition has been damaging but still made great headlines. Chaos in government, however, will have dangerous, real-world implications. The anti-government rhetoric that flourished on the so-called Alt-Right during the past eight years is about to get a reality check.
3) Demonstrate conservative credentials to unite the Republican Party
Trump may be unlikely to win over his critics on the Left but, with Republicans controlling Congress, that may not matter if he can unite his own side. However as the election campaign proved, that is easier said than done. Never mind the brash, divisive persona, the new president's ideological credentials have always been viewed with deep scepticism by many conservatives. Many voted from him in November with little enthusiasm, primarily concerned with stopping Hillary Clinton and a Democrat agenda.
On this task, Trump does have some useful immediate cards to play. An early appointment of a conservative Supreme Court judge should satisfy both the Republican base and establishment. So too the repeal of Obama-era laws that infuriated the Right. Expect Trump to assert his authority with several early executive orders reversing Obama acts, on touchstone issues like immigration, energy regulations and withdrawing from the TPP trade deal.
However again, his lack of consistent, coherent policy aims could prove troublesome. For example, the GOP have long sought to repeal the Affordable Care Act. Trump too has banged the drum on this issue, condemning rising costs but also promising that 'nobody will go without insurance', recognising that repeal will create immediate losers.
The plan is now to 'repeal and replace' simultaneously but formulating a replacement that doesn't cost more or generate a swathe of horror stories among patients will prove a painstaking challenge. So too will getting any bill that adds to entitlements through a Republican Congress.
4) Making early progress on signature promises is essential, yet will prove costly
There are two obvious ways which Trump can win over at least some of a hostile public. Drive economic prosperity, job growth and successfully execute the commitments for which he is most famous. Building the wall with Mexico and public infrastructure would achieve both ends and provide visible evidence that he gets things done.
The problem, as ever, will be the cost. Unless Mexico suddenly agree to paying for the wall or an avalanche of private investment appears, the money for these projects will have to be borrowed. Yet Republicans at both government and grassroots level are vehemently opposed to extra public spending. It may be possible to get the support of some Democrats for infrastructure spending, except for the fact Trump's hateful relationship with the Left will make building alliances near impossible in the short-term.
If he's blocked, the wall may soon become a fence, or even merely a virtual wall. The infrastructure and the jobs may take years to arrive or even never materialise. In that case, the businessman who gets things done may come to be regarded as just another do-nothing politician.
5) Calm nerves both around the world and among the US foreign policy and intelligence communities
The view from outside is probably not clear to the American public, or even perhaps to Trump himself, but the effect of his campaign rhetoric is about to hit home. When the Trump administration comes to dealing with foreign governments, they will hear fraught concerns about trade wars, post-WW2 military alliances and the temperament of the man now in possession of the nuclear codes. When Trump visits foreign countries, he will find overwhelming, hostile opposition.
Everything the US President says or does has international ramifications. Trump speeches or tweets about specific companies or sectors have already forced instant falls in their share price. Now, there is widespread fear that a 3am tweetstorm could start a war. Twitter and shooting from the hip served Trump the candidate well but the President must start acting and communicating like a statesman.
These concerns aren't exclusive to non-Americans. Foreign policy experts of all political stripes worry about Trump and his advisors' lack of knowledge or experience. Suspicion regarding his relationship with Vladimir Putin and war of words with the intelligence community persists, with a stack of questions still unanswered. We are all, not least Trump himself, entering unchartered and unpredictable territory.