The U.K.-based defense and security think tank Rusi released a report ominously titled “Preparing for War in Korea.

“War is now a real possibility,” wrote report author Malcolm Chalmers, the think tank’s deputy director-general. He laid out reasons President Donald Trump could surprise North Korea and other informed observers and follow through on his threats to attack Pyongyang.

While the president could decide the U.S. cannot live with a nuclear-armed North Korea, he could also start a conflict to boost his popularity rating or to distract from the ongoing investigation into his campaign’s possible ties to Russia.

According to Chalmers, Trump has demonstrated a keen awareness of how his actions affect his popularity rating, referring specifically to how his numbers rose temporarily after the U.S. airstrike against Syria in April, in response to allegations that President Bashar al-Assad used chemical weapons.

“War against North Korea might produce a similar outcome, at least in the short term, rallying public support behind the commander-in-chief and dividing his Democratic opponents,” Chalmers wrote. “He might also believe that it would be difficult for the mainstream media to maintain their focus on his past ties with Russia when U.S. forces were fighting and dying in a Korean war.”

The report also says Trump could take action against North Korea as a way to further distance himself from his predecessor’s legacy, or to further establish his “America First” ideology.

“A decision to attack North Korea, seeking to protect the U.S. from a possible future threat, even if this risks devastating attacks on regional allies, would be the most striking demonstration of America First so far, defining a Trump presidency just as surely as the Iraq War did for President George W. Bush,” Chalmers wrote.

The situation on the Korean Peninsula remains tense, as Trump and the North Korean regime trade insults and threats. North Korea’s foreign minister recently said Trump’s Twitter threats constituted a declaration of war, also saying Pyongyang was ready to shoot down bombers even outside the North Korean airspace.

So far, the U.S. military has not seen “a change in posture of North Korean forces,” as Joint Chiefs of Staff Chairman General Joseph Dunford told a Senate Armed Services Committee hearing this week, though North Korea has claimed that millions of people signed up to join the country’s 1.2 million active troops days after Trump promised to “totally destroy” the rogue state.