Diplomacy failed to stop Pyongyang from getting the bomb. Trump didn’t make the same mistake.
And
President Trump decided to use military force to stop Iran from getting a nuclear weapon after diplomacy failed. This was a choice, as critics are quick to note, and a risky one. But the strangely forgotten US experience with North Korea suggests the alternatives were even riskier.
Nothing more to add; it’s hard to get any clearer.