In the last few weeks, the leaders of practically every country I've looked at have seen their approval ratings improve significantly. An obvious conclusion to draw is that this is due to the COVID-19 pandemic.
To give a few examples, President Trump's approval rating has jumped 5 points to an all-time high, and UK Prime Minister Boris Johnson's approval rating has improved by 12 points since the December general election, while his Chancellor, Rishi Sunak, has seen his net popularity soar from -6 to +49.
In mainland Europe, President Macron's approval rating has improved to a two-year high and german national voting intention polls have shown an increase of 4% in the last fortnight for Chancellor Merkel's CDU party.
I am reminded also of the effect of the 9/11 attacks, which saw President Bush's approval rating soar from 51% to 90%.
Has any research been undertaken which explores the effects of national or international crises on leaders' popularity? Is there some sense of need for national unity that is evoked?