How has the 3 branches of government evolved over time?

The American government has three branches. You probably knew that. The executive branch is focused on daily administration of the country and is headed by the president. The legislative branch makes laws and is encompassed in the US Congress. The judicial branch interprets and upholds the law under the Supreme Court.

So, we've got these three branches, and each one has powers over the others to make sure that no one group can ever be too powerful. Think of it as a political version of rock-paper-scissors. President vetoes Congress, Congress undermines Supreme Court, Supreme Court overrules president and Congress, paper covers rock, rock breaks scissors, scissors cuts paper.

This delicate balance of power is written into the US Constitution, but it's actually changed over time. None of the three branches looked the same in 1787 as they do now, but as long as they changed together, no branch became more powerful than the others, and the game continued.