WASHINGTON — Amid the gravest challenge of his presidency, public opinion polls have delivered some good political news for President Donald Trump: a small uptick in his approval rating, in some cases to the highest levels of his tenure.

The bump, around 2 to 5 percentage points depending on the poll, has cheered Trump supporters who argue that it shows the public responding to his leadership, and confounded critics who see an erratic president veering between strategies after weeks downplaying the threat.

Polling experts say even a small upward movement for Trump is meaningful, but they add caveats: His bump is smaller than presidents typically get during national crises; it lags that of other political leaders and it’s still early to measure the views of his performance amid an unpredictable, sweeping crisis likely to play out for months.

A small shift — but meaningful for Trump

Trump’s polling has been remarkably stubborn throughout his presidency, stuck within a narrow range and suggesting that attitudes about the president are fairly fixed, seemingly no matter what is happening in the world. That’s why even relatively small recent movements in numerous polls have caught attention.

“For there to be any change I think is notable, and I think this is a significant positive change,” said Carroll Doherty, the director of political research at the nonpartisan Pew Research Center. His poll, concluded March 24, showed a 5 percentage point increase in approval for Trump since January — up to 45% (though more people still saw Trump’s work negatively than positively).

“While it’s not large ... it is statistically significant and it brings him right back to where he was in March 2017, in the early months of his presidency,” Doherty said.

Gallup also showed a 5 percentage point uptick, to 49% approval, matching the best of his presidency. And a Washington Post/ABC poll concluded March 25 found Trump with a 48% approval against 46% disapproval, the first time that survey found a net positive approval.