The electorate is constantly in flux. And so it has always been in NYC, which would of course be a Dutch island like Curacao if it hadn't been.
Big influxes of Eastern European Jews, Catholic Irish and Italians, Puerto Ricans, not to mention southern blacks and New England bankers.
You may have a point that we should look at naturalization laws ... are they too lax? Do they allow too many people to become U.S. citizens too quickly? I'm actually kind of mystified by how much time we spend on birthright citizenship (which is in the constitution) vs. naturalization, which is expressly a power of Congress to change as they see fit.