Given what we've seen in his term so far, scandal and corruption seem unlikely to rattle him or his base.
Is there a star candidate in the Democrat camp threatening to galvanise opposition and drive a record voter turn out?
Perhaps it's too early to be sure but from what we've seen of the crowded field so far it doesn't look much like it.
That leaves the economy ... stupid (to misquote Bill Clinton's classic line).
Trump unleashed his enormous fiscal stimulus plan early in his term.
That turbo-charged an economy that was already in the middle of a strong recovery.
In the short-term it has given him plenty to tweet about. He's presided over stock market records, strong employment figures.
But economists say the stimulus has played out. The International Monetary Fund forecasts that US growth will dip below two per cent next year.
Trump's running an enormous deficit and needs rate cuts to drive growth from here.
He's not shy about admitting that - tweeting furiously at the US Federal Reserve to cut rates more dramatically than they have, or plan to.
In New Zealand even the most optimistic economists are now picking two more rate cuts this year.
The latest to take a gloomy turn was BNZ's Stephen Toplis. Last week he added a November rate cut to his expectation of a cut this week.
He also warned that the indicators now point to sub two per cent growth.
While that's not recession territory yet, it does put us in the danger zone. We become vulnerable to one-off shocks like a dry summer or commodity price slump.
Trump's spin is that he's presiding over the greatest US economy in history.
Our Government's slightly more down-to-Earth line is that we're in a managed transition to a more sustainable growth path.
The reality is that we're largely in the same boat with most of the Western world.
We're stuck in a low-growth, low-inflation, high-debt economy which relies on low interest rates to keep the businesses and households ticking over.
Technology has stopped driving productivity. Wages aren't rising.
We're all struggling with structural issues that our traditional economic policies can't address.
Trump's trade war with China isn't helping but it's the not the fundamental cause of this slowdown.
The New Zealand Government is at least talking about long-term policies but, like the Trump administration, it seems to be in denial about the short-term economic risks.
If Trump can't pump the economy he'll have to rely on ever more dramatic attack strategies to play to his base and hope the quirks of the US electoral college get him over the line.
Ardern could rely on personal charisma, global star power and hope the quirks of New Zealand's MMP system get her over the line too.
That would be a shame. It's too early for this government to be playing for time.
How often do we see a winning team pile on a big lead early, only to spend the second half on defence – throwing the momentum to the opposition?
If Labour wants to hold power next year, it needs to put more points on the board.
It needs to acknowledge that this economy is very different to the one it inherited.
Unlike many in the business community, I don't think the downturn is all of the Government's making.
But it needs to be acknowledged and plans to deal with it need to be made.
That might well mean fiscal stimulus - spending on roading and infrastructure - or even some form of tax cuts.
Right now, business as usual for this Government puts it at risk of being pipped at the post – or scraping across the line for an unpopular second term.