There is no doubt; impeachment is a political act. It might be instructive to consider the 4 times when impeachment has been a possibility since the end of WWII.

Richard Nixon - The first time is always the hardest, and although Nixon's crimes may seem a bit quaint by today's standards, the inevitably of the evidence and the combination of relentless pressure from the press and sheer mean-spirited, bull-headed obstinacy from the White House were steering the nation toward a constitutional abyss. Nixon showed more class and more honor by resigning than any of his critics ever gave him credit for. There were two unanticipated consequences, though: the right wing became determined to get its revenge, no matter what the cost, and the press, perhaps astonished by their own power, lost the nerve and the confidence to ever use it again.

Ronald Reagan - Caught red-handed conducting his own private war against the will of Congress and negotiating secretly with Iranian terrorists, the teflon president somehow managed to even evade censure. The cowardice of the press, and what I believe was their fear of losing ratings in an increasingly conservative country by attacking a popular president, allowed him to get away with not just an impeachable offense, but treason. It was the beginning of the end of the American century, as the nation's innocence was transformed instantly, in the eyes of the world, into unforgiveable hypocrisy.

Bill Clinton - After his predecessor's crimes, that Clinton's fleeting fellatio could lead to impeachment proceedings is inconceivable, no pun intended, but we all saw it happen, didn't we? The Right had its revenge, but the press never did find its balls; the sex and the hearings made great television. Of course, the conservatives still weren't satisfied, and they innoculated themselves further from media scrutiny by somehow convincing themselves and the press that it was biased and "too liberal". Of course, the press is neither, but it IS a business, and the news divisions are now fully committed to infotainment.

Bush the Younger - No, George W Bush has committed no impeachable offense, stupidity and incompetence are not yet constitutional crimes. His bungling of the Iraq war was carried out with the full complicity of Congress, and the American people as well. If it can ever be proven that the decision to conduct premptive war was not based on faulty intelligence, but on a deliberate conspiracy to fake the evidence in order to create an American puppet and military base in the Middle East, there might be grounds, but I don't think that will happen. They're just not that smart.