Okay kiddo, so Trevett v. Weeden is a really old court case that happened in the United States a long, long time ago. It was about some farmers who were upset because they had to pay extra taxes on their sheep and rams.
These farmers thought that the taxes were unfair because they believed that the government didn't have the right to make them pay more money for their animals. The case went all the way to a really important court called the Supreme Court, where judges had to decide whether or not the farmers were right.
In the end, the judges decided that the government did have the power to make people pay taxes on their animals. They also said that this power was important for the government to be able to do their job well and keep things running smoothly.
So even though the farmers didn't win their case, it helped to establish an important legal principle in the United States that the government has the power to tax its citizens.