Electoral college. Idaho always goes red, Oregon always go blue. Moving population from Oregon to Idaho transfers electoral votes from a blue state to a red state.
Whether it matters or not depends on whether it changes the tipping point state in any given election, which is hard to know in advance, but for the red team it is at worst identical to the current setup and at best a small boost to their chances in a presidential election. Conversely for the blue team it can either be meaningless or a slight negative.
American hegemony was a conscious American policy choice. We didn’t want the Euros having an independent foreign policy, we wanted them reliant on American military protection. This was how the US kept those bits of its empire in line.
Notice how the only Western European country that even pays lip service to independent action is France, the one Western European country with a military capable of independent operation. And then we get “Freedom Fries” and all that shit whenever they don’t do whatever the current US admin wants.
The single biggest thing Trump fucked up for the US was pushing NATO countries to spend more on defence. This will drastically reduce US influence over the continent in the coming decades, speeding up America’s worsening diplomatic isolation.