Okay, little one, let me explain it to you in a way you can understand.
First, do you know what election campaigns are? It's when people running for office try to convince people to vote for them by telling them about their plans and ideas.
Now, there are rules about how campaigns can raise and spend money. One of those rules is that groups called "political action committees" (PACs) can't spend unlimited money to help a particular candidate win.
That's where FECA and Wisconsin Right to Life come in. FECA stands for Federal Election Campaign Act, and it's a law that sets rules for election campaigns. Wisconsin Right to Life is a group that wants to help certain candidates win.
Wisconsin Right to Life wanted to buy ads on TV and the internet that talked about certain candidates and their positions on issues related to abortion. But FECA said that wasn't allowed because it would count as too much money spent to help those candidates.
Wisconsin Right to Life disagreed and said that the ads were just talking about issues and not telling people to vote for a particular candidate. They took the case to court, and the Supreme Court eventually decided that their ads were allowed under the First Amendment (which protects free speech).
So, in summary, Wisconsin Right to Life wanted to buy ads supporting certain candidates, but FECA said they couldn't spend too much money doing that. The Supreme Court eventually decided that the ads were okay because they were protected under the First Amendment.