Post WW2, US and USSR emerged as two contending superpowers. End of cold war saw USSR wanning and US emerging as sole super power. Ever since then, the US has maintained its hegemony on the globe. To every rise there is a fall. It appears that, US hegemony is being challenged on multiple grounds. At the grand strategy level, China has put US in a reactive mode. Wanning of the super power is definitely going to take time, but how much; remains in debate. George Fiedman in ‘Next 100 Years’ seems overtly optimistic, while contending that next complete century belongs to the US. However, there are indications which can prove him wrong. Farid Zakaria sounds more realistic in his book, ‘Post American World’. At global level there are signs of wanning like; surrendering space in global leadership, being reactive, displaying frustration, losing allies and subordination of countries. In 1991, whole world was with the US, in War against Iraq, in 2001 War against Iraq, half of the world stood by the US, whereas, in 2017, in UNSC on Recongnition of Jerusalem as Capital of Israel no one was with the US. That’s how US has lost in global leadership. If we take homeland issues, there too, the US is fast losing ethical standing. I see practices akin to 3rd world gaining grounds in the US. Daughter of POTUS running office in White House. Trump making his incumbency a must for economic well being of the US and extra ordinary powers to police and intelligence organisations should have been ethically alien to superpower but these are there. In all fairness the US wanning may complete in 3-5 decades. However, a frustrated, agitated and reactive sole superpower led by a mercurial leader is extremely dangerous for the world peace.