President Trump's credibility is put to challenge as North Korea has repeatedly defied US military power and for the second time, successfully launched a ballistic missile on Sunday, May 21, 2017. Now the question becomes what will President Trump do, besides reciting the rhetoric of economic sanctions and political diplomacies. As a matter of fact, it's not President Trump, but the US, needs to act, to take tangible actions to curb North Korea's belligerent behavior. The consequence for not acting may be as disastrous as going to war: US would lose her credibility as the international police, the world's superpower, and symbol of world peace. This is detrimental to global growth, stability, and prosperity.