The Impeachment process is used against a President, Vice President or a U.S. Official. When any of this positions make any type of treason, bribery or any kind of high crime, any legislative body can press charges against the accused. It is needed a majority of votes for a minor crime and a two-thirds vote for a major offense.
Impeachment has PROS and CONS (using as an example the impeachment for a president). A PRO could be that if the Vice President has stronger ground in politics, the impeach of the president will put the Vice President as the new American leader and as a result, create a stronger government.
A CON could be an impeachment fail. If we use Clinton's impeachment as an example, he became more popular and grew his followers thank of the impeachment.