US President Donald Trump may have a personal interest in keeping the rest of the world wondering what he is actually up to. But the pervasive sense of uncertainty he has created since Day 1 in the White House is hardly conducive to his presidency or US national interests, never mind global stability.

If his frequent verbal flip-flops on major issues in his first days in the Oval Office were forgivable for a man new to politics, the messy state of affairs he continues to create now may have harmful consequences.

The US president has demonstrated an obvious belief in the applicability of his business acumen to state-to-state relations. Or he would not have been so vociferous about renegotiating key international treaties and trade pacts to which the US is a party. He is known for his preoccupation with immediate US gains, so much so that he has left the US' closest allies worrying.

If those were the inevitable side-effects of his businessman's persona that are more annoying than harmful, the suspense he is creating on key matters of international concern is different. Particularly his idea to withdraw from the Iran nuclear agreement and veiled threats to use force against the Democratic People's Republic of Korea.

Although he is yet to announce that withdrawal, or clarify what he was referring to when he said "only one thing will work" with Pyongyang, those are words that would have serious consequences if put into action.

Trump may believe the US' unrivaled capabilities give him boundless room for maneuver in handling foreign policy issues. But in that he would be mistaken.

Scrapping the Iran nuclear pact, like pulling the trigger on Pyongyang unprovoked, will not advance US interests, unless Trump has a way to limit the repercussions of those actions.

But chances are he has not, and the world is already dealing with the consequences of the US acting without thinking about what comes next.