The Guardian on Wednesday published an interview with John Bolton, the former US National Security Adviser, who warned that Donald Trump's second term could bring a heightened risk of international crises due to the president-elect's impulsive leadership style and lack of focus on foreign policy.

Bolton, who served under Trump for 17 months, described his former boss as uninterested in the complexities of international relations, stating, "He doesn't know much about foreign policy. He's not a big reader... briefing papers are almost never read because he doesn't think they're important." He criticized Trump's decision-making process as guided by "neuron flashes" rather than coherent strategy, adding that "intellectual discipline wasn't in the Trump vocabulary."

Highlighting the increased risks in today's geopolitical climate, Bolton cautioned, "The risk of an international crisis of the 19th-century variety is much more likely in a second Trump term. Given Trump's inability to focus on coherent decision-making, I'm very worried about how that might look."

Bolton expressed particular concern over Trump's claims that he could end the war in Ukraine within a day, suggesting the president-elect might push for a resolution without considering its consequences for US allies. "He wants it behind him, which strongly implies he doesn't care on what terms," Bolton said, warning such an approach could be "very dangerous for Ukraine."

Read more: NATO leaders urge defense boost amid concerns over potential US shift

The former ambassador to the United Nations also criticized Trump's admiration for authoritarian leaders like Vladimir Putin, Xi Jinping, and Viktor Orbán, saying, "Trump likes being a big guy, likes other big guys. These other big guys don't have pesky independent legislatures and judiciaries... He just wishes he could do the same."

Bolton acknowledged that Trump's decision-making relied heavily on personal relationships, often at the expense of national security. "If you put everything on the basis of personal relations and you don't understand how the person you're talking about on the other side views you, that's a real lack of situational awareness that can only cause trouble," he explained.

Bolton's criticisms also extended to Trump's recent controversial proposals, including threats to reclaim the Panama Canal, purchase Greenland, and annex Canada. Reflecting on the potential unpredictability of another Trump presidency, Bolton remarked, "He now feels more confident in his judgment having been re-elected, which will make it even harder to impose any kind of intellectual decision-making discipline."

Despite his scathing assessment, Bolton expressed hope that the Republican Party would eventually return to its traditional values, calling Trump "an aberration" and predicting that once he leaves the political scene, the party would "snap back."