I understand your point, but WE live in a post-colonalization World Order - all countries (or nation-states) have internationally recognized borders in current times. United Nations (UN) gives legitimacy to internationally recognized borders.
US was established by European settlers with ample life-experience. These people came together to establish a new identity in the Americas and challenged British supremacy in the region. These people fought for independence and secured it in 1783.
US also have history of fighting wars to expand its territory in pre-UN times. US was composed of 13 states in 1783. But US decided to fight for more lands and managed to create 50 states in 1848, US annexed a chunk of Mexican Empire and wiped out Red Indians in the process.
Alaska is the only state that US acquired peacefully in 1867, then Russian Empire agreed to sell Alaska to the US.
US was globally recognized as a world power when it defeated Spanish Empire in a war in 1898 and took control of several Spanish colonies in the aftermath. US also liberated Cuba in the process.
US and the British Empire found common grounds in both World Wars but UN was founded in 1945 and the British granted independence to numerous colonies after 1945.
US is among the original founding members of UN, and has not fought to colonize other countries since. US has ample natural resources and can meet its needs in the foreseeable future.
US exerts its influence in other ways such as through its financing institutions, investments, soft power, and regime change experiments.
US can revive colonization but how it will justify this move in current times? US will have to shut down UN in the process.
It will be a free-for-all world again.
US will find it easy to colonize other countries because there is no need to consider nation-building to win hearts and minds in another country. This is all about muscle, and US has plenty of muscle.
US and Russia might even be allies in colonization projects. Russia has no beef with US, Russia simply does not want US to stop it from eating neighboring states.
