The fundamental challenge facing the US is that it is relentlessly losing in peaceful economic competition to China. The US therefore cannot maintain its global dominance through economic means and so it is increasing stepping up its use of political and military aggression to try to stop China’s economic rise.
The US’s economic position has weakened greatly. But its military power is still very great. Therefore, the US attempts to move issues onto the military terrain. This explains its escalating military aggression.
A recent report on climate change from the US military argues that the impact of climate change would require military interventions at home in the US and abroad that would be too great for the US military to cope with.