The natural home for nativist immigrant haters and fear mongers is the Republican Party that controlled both the House and Senate until January 2019. They were the ones that took no action to protect Parkton against the peril of illegal immigration.
I strongly suspect that this was intentional. Any interest in legislation that would meaningfully resolve the issue of illegal immigration to the satisfaction of their constituents would cause the issue to go away and the GOP could not rely on the paranoia like the letter writer expresses as a get-out-the-vote technique. The best thing for the Republican party nativist politician is the status quo of doing nothing.