read the Constitution
Everything else is opinion.
http://www.usconstitution.net/const.htmldo "find on this page" and find the word "impeach"
You'll find:
The House of Representatives shall chuse their Speaker and other Officers; and shall have the sole Power of Impeachment.-snip-
The Senate shall have the sole Power to try all Impeachments. When sitting for that Purpose, they shall be on Oath or Affirmation. When the President of the United States is tried, the Chief Justice shall preside: And no Person shall be convicted without the Concurrence of two thirds of the Members present.-snip-
Judgment in Cases of Impeachment shall not extend further than to removal from Office, and disqualification to hold and enjoy any Office of honor, Trust or Profit under the United States: but the Party convicted shall nevertheless be liable and subject to Indictment, Trial, Judgment and Punishment, according to Law.-snip-
The President shall be Commander in Chief of the Army and Navy of the United States, and of the Militia of the several States, when called into the actual Service of the United States; he may require the Opinion, in writing, of the principal Officer in each of the executive Departments, upon any subject relating to the Duties of their respective Offices, and he shall have Power to Grant Reprieves and Pardons for Offenses against the United States, except in Cases of Impeachment.-snip-
The President, Vice President and all civil Officers of the United States, shall be removed from Office on Impeachment for, and Conviction of, Treason, Bribery, or other high Crimes and Misdemeanors.
-snip-
The Trial of all Crimes, except in Cases of Impeachment, shall be by Jury; and such Trial shall be held in the State where the said Crimes shall have been committed; but when not committed within any State, the Trial shall be at such Place or Places as the Congress may by Law have directed.That's it.
The "shall be removed from Office on Impeachment for, and Conviction of, Treason" is pretty compelling. It does not say "could be, if the mood of the country is right"
It says "shall be". In legalese "shall" is different from "will" and vastly different from "can be." And since the house has the sole power to impeach, you make a pretty compelling case that they must - it says "shall" and nobody else can do it. However, it says "shall be removed upon conviction" - so one could argue that it does not say "shall be impeached if suspected of treason" and therefore they get to sit on their hands. They can fulfill their obligation to "uphold the constitution" by doing nothing. It is said that the framers of the Constitution were intentionally vague - they did not want to dictate, to force the issue. They left it up to their successors in leadership of the country. Little did they know that leadership would be usurped by George V's successors.
If there is a case for Treason, there is no quibble over what constitutes "high crimes and misdemeanors." the Plame outing would be one, the whole deceit to go to war would be another, funding terrorist groups would be another. Gotta pin them on bush personally though. He can try to pull a gonzo and just play dumb. Is it treason to be an absolute idiot while your appointees commit treason?
I suspect that investigations could actually uncover a case for bribery as well. Lord knows most of the congresscritters on both sides of the aisle, while not necessarily provable, are getting fat off the public and doing the will of special interests to do so. If that's not bribery in the pure sense of the word, it's damned close. Hastert's millions made off land deals in Illinois are a prime example. Sumbitch was a high school wrestling coach, got elected to Congress, now he's a multimillionaire. Do the math. But I digress. It is probable that there are deals that enrich bushco. Cheney? Little doubt in my mind. All those no-bid contracts enrich their cronies, and one has to suspect there's a quid pro quo there somewhere.