When Sen. Roger Marshall went back to Kansas over Thanksgiving, he said he took his grandkids sledding and saw old friends. But everyone he talked to was worried about the southern border, he said on the Senate floor. “In Kansas, the heartland, the middle of the country, the middle state, people are concerned about their own safety and security,” Marshall, a Kansas Republican, said last week. As Senate Republicans are pushing for Congress to pass stiffer immigration policies in the final weeks of the year — limiting asylum claims, preventing people who cross the border illegally from being par…