First, the good news. Donald Trump almost certainly does not wish to go to war with China over the disputed islands in the South China Sea. Yes, in his Senate confirmation hearing in mid-January, secretary of state nominee Rex Tillerson provocatively compared Beijing’s moves in the sea to “Russia’s taking of Crimea” and said its “access to these islands also is not going to be allowed”. And on Monday, White House press secretary Sean Spicer pledged to defend “international territories” in the South China Sea.

But the simplest – and, frankly, more believable – explanation is that both men misspoke.

In the same hearing, Tillerson mistakenly said $5tn in trade passes through the South China Sea daily – it’s yearly. Trump’s team is new, relatively inexperienced in foreign policy and less reliant on expert briefings. As Dennis Wilder, the top White House Asia adviser to George W Bush, put it: “Tillerson and the new press secretary are just not yet steeped in the arcane nature and legal niceties of the South China Sea issue.”

Moreover, blockading the islands is not only “literally an act of war”, but “operationally almost impossible” an American South China Sea expert, who asked to remain anonymous because of the sensitivity of the situation, told me. And that, he said, indicates “it is a temper tantrum” – one that Trump may be using with the intention of trying to exert trade concessions from China – and “not a believable threat”.

That is the good news.

The bad news is that if in the coming months or years Trump faces an ignominious end to his presidency through scandal or mismanagement, a national crisis – involving China, or Isis or another foreign actor – could allow him to cling to power.

After national crises involving foreign actors, presidents often enjoy a bump in popularity. John F Kennedy, for example, saw his popularity shoot up after the Cuban missile crisis, while after the 9/11 attacks in 2001, George W Bush’s approval rating jumped from the mid-50s to a record high of 92%. In December 1979, the Republican presidential candidate John Connally reversed his earlier criticism of Jimmy Carter’s handling of the ongoing Iranian hostage crisis. “We have only one president,” Connally said. “Now is the time to rally behind him and show a solid front to Iran and the world.”

Political scientists call this the “rally round the flag effect”, and there are two schools of thought for why it happens, according to the scholars Marc J Hetherington and Michael Nelson.

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There’s the “patriotism” school, where the president embodies the spirit of the nation, earning himself a place above criticism, and the “opinion leadership” school, where “leaders’ unwillingness to criticize leaves journalists with nothing to report – and citizens with nothing to read, see or hear – that is not supportive of the president”.

Trump surely understands this, and may be tempted to aggravate a national crisis in order to protect himself. He is a keen student, not of history – he said recently that his two favorite books were ones that he himself wrote – but of human psychology, and especially of mass appeal.

If Trump exacerbating a tense situation into a national crisis, or even a war, in order to save his presidency sounds far-fetched, consider his palpable insecurity, and how he obsesses over signs of his popularity. Trump’s White House continues to insist that his inauguration crowd was the largest ever, and that he only lost the popular vote because of massive election fraud – both obvious lies. For Trump, public acclaim seems to justify his existence.

Also, Trump enters office beleaguered. His approval rating is the lowest for a new president since Gallup begun surveying the issue in the Dwight D Eisenhower era. And his myriad financial interests, his refusal to release his tax returns, his impulsiveness, his penchant for nepotism, and his willingness to mix business and pleasure greatly increase the chance for an impeachable scandal.

Moreover, Trump has shown himself masterful at hijacking the national conversation to redirect attention away from his scandals and incompetence: “the Distractor in Chief”, in the words of the Washington Post’s Paul Farhi. A state of national emergency following an Isis attack, or a war with China to, say, “steal our jobs back” would follow that same pattern – only amplified. We underestimate his desire to maintain that popularity, and the tactics he would employ to do so, at our own peril.

Yes, the rally round the flag effect is temporary – lasting only a few weeks to several years, depending on the nature of the crisis. And presidential popularity can suffer when a war imposes financial and societal costs. But its effect is real.

If Trump is voted out of office, or impeached and convicted, it does not matter what threat the US is facing. It does not matter if we find ourselves enmeshed in a war with China, or scrambling to respond to an unprecedentedly devastating terrorist attack. He must go.

“In times of national crises,” Hetherington and Nelson wrote, “Americans rally to the president as the anthropomorphic symbol of national unity – a kind of living flag.” In some ways, our national nightmare would be a Trump dream: a period where his acclaim is absolute and unimpeachable.

