As the early stages of the campaign for the United States' 2020 election get under way, President Donald Trump's support base, while relatively narrow, remains unshakeable.
But his problem may be that despite the robust economy, his appeal has not broadened beyond his base.
His average approval rate has hovered between 36 per cent and 45 per cent, a fluctuation of nine points, over practically the entire course of his presidency, according to the presidential approval tracker of political analysis website FiveThirtyEight.
This may be partly because in a time of extreme polarisation, attitudes towards Mr Trump are set and hardened, said Mr Charles Cook, editor and publisher of the Cook Political Report.
Mr Trump's approval ratings have consistently been lower than those of the last eight presidents who sought re-election.
"His job approval ratings (have been) not only consistently below the six that did get re-elected, but also below the two that did not get re-elected," Mr Cook told The Straits Times.
Across various major polls by Gallup, ABC-Washington Post, CNN, Fox, Pew Research, NBC-Wall Street Journal and the Kaiser Foundation, there was very little disagreement, he said. "They are all saying basically the same thing - that for a President in a first term, at each point on the way, he's below where everybody else has been."
Part of this has to do with partisanship. "Typically 80 per cent to 91 per cent of Republicans approve of the job he's doing, and lately it's been more 87 per cent to 90 per cent, and that number doesn't move up," Mr Cook said.
"And single digits of Democrats approve of the job he's doing and that doesn't move much."
At the extreme ends of the spectrum, 61 per cent of Republican men strongly approved of Mr Trump in a Fox News poll.
But just 2 per cent of Democratic men, and 2 per cent of women, strongly approved of him.
And 81 per cent of Democratic men strongly disapproved of him, while 5 per cent of Republican men strongly disapproved of him.
"Part of it is the partisanship, and part of it is the intensity; 70 per cent to 75 per cent of Americans have a strong view of him," Mr Cook said. "They either strongly approve, not somewhat approve, or they strongly disapprove, not somewhat disapprove."
And polls also show that for every person who strongly approves of Mr Trump's performance, 1.4 to 1.8 strongly disapprove.
The maths clearly does not favour Mr Trump, and his fate will boil down to independent voters.
"Roughly 35 per cent of voters are going to vote for him no matter what," Mr Cook said.
"Then there's 45 per cent who are going to be against him no matter what. That leaves 20 per cent in the middle that is going to tip this election one way or the other."
He added: "Normally, one percentage point is enough to win. President Trump has to win between two-thirds and three-quarters of that 20 per cent that's in the middle, and that's very challenging."
It is early for predictions, but on the day in 2020, the outcome will also depend on whether Democrats unite behind a candidate, rather than remaining split as in 2016, when many Democratic Party supporters who preferred Mr Bernie Sanders were not enthused about voting for Mrs Hillary Clinton.
But the numbers, and the signs, favour the Democrats, analysts say.
There is a new resolve among Democrats, Mr Cook told The Straits Times.
"They might prefer this candidate or that candidate, but they would vote for a potted plant against Donald Trump. We saw that unmistakably in the 2018 midterm elections, and I see no reason he can and will say or do anything that will diminish that.