Reply #86: Thanks for bringing that up! I did a Google! According to C-Span's Congressional Scholar

[DianaForRussFeingold]

The Constitution says a President can be impeached for "high crimes and misdemeanors," but it doesn't define the term. Who decides what that means? Columbus, Ohio - 5/3/00

The Congress decides the definition: by majority vote in the House for impeachment, and by 2/3 vote in the Senate for conviction. The Framers of the Constitution deliberately put impeachment into the hands of the legislative branch rather than the judicial branch, thus transforming it from strictly a matter of legal definition to a matter of political judgment. Then Representative Gerald Ford put it into practical perspective in 1970, when he said an impeachable offense is "whatever a majority of the House of Representatives considers it to be at a given moment in history."
"High crimes and misdemeanors" entered the text of the Constitution due to George Mason and James Madison. Mason had argued that the reasons given for impeachment -- treason and bribery -- were not enough. He worried that other "great and dangerous offenses" might not be covered, and suggested adding the word "maladministration." Madison argued that term was too vague, so Mason then proposed "high crimes and misdemeanors," a phrase well-known in English common law. In 18th century language, a "misdemeanor" meant "mis-demeanor,"or bad behavior (neglect of duty and corruption were given as examples), while "high crimes" was roughly equivalent to "great offenses."

Lawyers and historians are still arguing about the exact meaning of "high crimes and misdemeanors," dividing into three schools of thought about the appropriate definition: (1) serious criminality evidenced by breaking existing law; (2) an abuse of office, and (3) the Alexander Hamilton standard (Federalist 65) of "violation of public trust." more... http://www.c-span.org/questions/week119.htm
Articles of impeachment, resignation, and convictions concerning Nixon
Interesting read http://en.wikipedia.org/wiki/Watergate_scandal#Articles_of_impeachment.2C_resignation.2C_and_convictions Published on Friday, April 2, 2004 by NOW with Bill Moyers
Ex-Nixon Aide John Dean Tells Bill Moyers that Bush Should Be Impeached Partial Transcript
http://www.commondreams.org/headlines04/0402-16.htm Video- http://www.pbs.org/now/politics/dean.html# These 2 videos are the best and clearest explanations I've heard and from someone who's been there! John Dean - Bush administration worse than Watergate -- video http://www.youtube.com/watch?v=f70B-gfKuxs