U.S. is number one but the kind of welfare path it has chosen it remains to be seen when the real sinking of US starts.
The case with China is slightly different. They are not a democracy and hence can afford to spend lot more money on tanks and nuclear warheads while millions rot in poverty. This is not possible for a country like India. So as Chinese economy grows its global influence is going to grow more exponentially than say that of India. Countries who become global powers try to impose their worldview on others for example US has pushed democracy everywhere and I am reasonably sure China is going to put "state knows the best" attitude everywhere they go.
The case with China is slightly different. They are not a democracy and hence can afford to spend lot more money on tanks and nuclear warheads while millions rot in poverty. This is not possible for a country like India. So as Chinese economy grows its global influence is going to grow more exponentially than say that of India. Countries who become global powers try to impose their worldview on others for example US has pushed democracy everywhere and I am reasonably sure China is going to put "state knows the best" attitude everywhere they go.