How was the impeachment of andrew johnson a test of the constitution system of checks & balances ?

You will now write an essay of at least three paragraphs that takes a position on an opinion in hazelwood v. kuhlmeier. you may choose to support the majority opinion or justice brennan's dissenting opinion. you should support your argument with reasons provided in the opinions, although you may also give reasons of your own. your essay should also decision in the case