The Tenther movement is a group of people who believe that the federal government of the United States has been overstepping its powers and infringing on the rights of individual states. They believe that the Constitution gives states the right to make their own laws and regulations, and that the federal government should only be able to exercise powers that are specifically granted to it in the Constitution.
So imagine that you and your friends are playing a game where you each have certain toys and you agree on rules for playing together. One of the rules is that you each get to decide what you do with your own toys, and your friend Jenny can only tell you what to do if she has a special rule card that lets her do that. But sometimes Jenny tries to tell you what to do even if she doesn't have the card, and you and your friends might think that's not fair because everyone agreed on the rules.
That's kind of like what the Tenther movement thinks is happening with the federal government and the Constitution. They believe that some things the government is doing are not allowed under the rules of the Constitution, and they want the states to have more power to make their own decisions. They might say that if the Constitution doesn't specifically say the federal government can do something, then it should be left to the states to decide.
Some people might agree with the Tenther movement and think it's important to make sure the federal government doesn't overstep its bounds, while others might disagree and think that certain issues require a national approach. But either way, the Tenther movement is all about trying to protect the rights of individual states and limit the power of the federal government.