can someone explain to me baker v carr

in little kid words? i don't understand what actually happened

In Baker v. Carr, the Supreme Court ruled that federal courts could decide reapportionment disputes. Each state is made up of congressional districts. From time to time, when population increases in one area or decreases in another area, the politicians draw different district boundaries. Each party tries to get as many districts who vote for that party as possible. Of course, arguments often occur about these boundaries. After the Baker v. Carr decision, federal courts can step in and set these district boundaries.

http://en.wikipedia.org/wiki/Baker_v._Carr