Okay kiddo, you know how we have a house with walls and doors to keep strangers out and keep us safe inside? Well, the United States is like a really big house with walls and doors too, but it has a really long fence called a border that goes all the way around it.
Sometimes, people who aren't from the United States try to come into the country without permission. Some people do this because they want to find jobs and make money to help their families, but others do it to do bad things like selling drugs or stealing. This is why we need to make sure our borders are secure and only let people in who have permission to come in.
In the United States, we have special people called border patrol agents who work really hard to make sure the border is safe and secure. They use tools like cameras and drones to watch for people who might be trying to cross over the border without permission. They also have special dogs that can sniff out things like drugs that people might be trying to bring across the border.
One other thing that the United States is worried about is terrorism. This is when people do really bad things like hurt other people because they want to make a point or cause fear. We want to make sure that people who might want to hurt our country don't come across the border.
So, to make sure we stay safe and secure, the United States is always working hard to make the border better and stronger. That way, we can all feel safe and happy in our big house with walls and doors (and a fence).