Impeachment seems to be presidential democracy's equivalent of parliamentary democracies' votes of no confidence. Why such a large disparity in numbers of them then?
One is an expected form of power transfer, the other is not.
In a parliamentary democracy, each representative has a mandate from their constituents, and only in aggregate can they form a government. If that government can't command a majority in the parliament, they basically can't govern, but someone else might be able to. Depending on the exact parliamentary model, this might then involve calling a general election "out of season".
Imagine you have 3 parties with the following seat breakdowns
- Red 35%
- Blue 45%
- Yellow 20%
At the start of the parliament, Blue and Yellow agree to work together, and form a government (the "Green Coalition"). They total 65% of the seats, so can easily pass their legislation. At some later point, they have a falling out, and Yellow ask Red to table a no confidence vote, which wins 55%, and then form a new government (the "Orange Coalition").
At no point have the choices of the voters not been honoured.
A president is chosen by all the people together. It's much harder to have a falling out with yourself over policy.
An impeachment is by design not honouring the choice of the voters, but putting some other criteria above it. The people who make that decision also answer to the voters, it's in their interest to only try it when they think the public will agree it was warranted.
Impeachment is a prosecution process; it only applies for gross misconduct, and the threshold for its success is really high. The PM can retire with only moderate shame after losing a vote of no confidence, but an president who is impeached and convicted ought to go to jail.
A vote of no confidence, on the other hand, simply indicates that the government is unable to pass critical legislation such as spending bills, and must be immediately replaced by a new government. The equivalent in the US process is more like the "government shutdown" that can be triggered by failing to raise the debt ceiling. In my opinion it's a serious bug in the US system that this does not trigger new elections.
Another key distinction is that the President in a presidential system is the head of state, and supposed to be somewhat more permanent. Corresponding to the monarch or Govenor-General in a Westminster system. The Prime Minister corresponds more to "majority leader".
Unlike parliamentary systems, the US opted for a system by which power would merely be transferred from person to person, until a new election cycle. So if you're going to Impeach (indict) a political figure, you need
- A solid reason for doing so. You can't do this on a whim and drum up some charges, you need the electorate to understand why an elected (or appointed) official is being removed.
- Political support. Impeachment is a political process. The Constitution, for instance, is intentionally vague on why a President may be removed ("high crimes and misdemeanors" is not a legal term). Remember, the people doing the impeachment will have to face their voters, and some of them may have voted for the person being impeached.
It's that second reason that has likely kept both impeached Presidents in office.
Keep in mind that resignation is more common. Richard Nixon would almost certainly have been impeached if he had not resigned.
Removal from office, following impeachment, at other levels is a bit more common,
Cannot stress enough that they are two utterly different things:
Impeachment is the process of determining an official has committed a, or several, crimes that are of a nature that he cannot continue in office. Note that AFTER impeachment occurs, there is a trial in which the official may be convicted (and tossed from office) or not convicted (and goes onward in office).
A vote of "No confidence" is one of several methods by which a parliamentary system of government's officials acknowledge that the current officials probably do not represent the current will of the people and that this is pronounced enough that a new set of officials is warranted (along with the expense and nastiness of an election). Actually, it would be better stated as "THE method by which..." as the main other methods of initiating an election are more arbitrary (a term length like, say, 7 years maximum, or a Head of State being able to "call" an election).
Nothing like each other.
Impeachment follows a crime, or six, while a vote of "No confidence" is basically an election call, no crimes involved.
As to the crimes considered for impeachment, in the US they tend to be crimes that undermine the government itself, governmental process, or the specific office's area of responsibility.
An example is a judge taking bribes. That undermines the judicial process itself. This is what he is usually impeached for. A particular federal judge from my area was impeached for this. Then, after conviction and removal, he was later charged with other offenses while in office (of the sort where he "leaned on" local officials to send work crews to build a nice driveway for him, a pool, and so on). He would probably not have been impeached for those crimes, though a higher court might have gone through the process of censuring him, removing him from cases, having him disbarred, and then, once disbarred, removed from office as no longer qualified for it. Those crimes hurt the county's basic governmental process, but not HIS office so...
Nixon probably wouldn't have been impeached for knowing about and approving of the Watergate break-in. It was the obstruction of justice, exacerbated by his firing of non-pliable officials in the Department of Justice like the Attorney General that would have been his trial articles. Clinton had the same issue: lying under oath to an investigating official (judge or not) obstructs justice. For Presidents, obstructing justice is like taking Olympic wrestling, writing scripts, and making it Big Time Fake Wrestling. It destroys the government itself in a way that a President accompanying the burglars in their burglary does not, hence impeachment.
Consider the last couple of paragraphs. Absolutely nothing in them is anything in the least like a vote of "no confidence" — they may seem similar, but they are utterly different.
I'd think the philosophy behind it is that it depends who "appointed" the official in the first place. In a parliamentary democracy, the voters chose the parliament, but the prime minister and other secretaries are appointed by the parliament.
A president, otoh, is "appointed" by all the voters.
So to cancel the appointment of a PM or secretary, it should be enough for parliament to cancel their decision, which can be done by a simple vote in parliament.
It's conceptually not that different from a president firing one of his secretaries, although usually when the PM is fired by parliament (vote of no confidence), that has more serious effects, as it's often seen as effectively a vote of no confidence on the entire cabinet/government. In the Netherlands, it means new elections, although I'm not sure about the situation in other countries.
The "cancellation of appointment" of a president should philosophically also be done by those who made the original decision: all voters.
Pragmatically, it's not useful to have to consult the entire population whenever something comes up, so usually it means a president can only be replaced when new elections are scheduled. And for extreme cases, there are provisions so that parliament/congress/senate/... can impeach a president if he is clearly not functioning well or has committed serious crimes. E.g. in the US, he can be impeached for "high crimes and misdemeanors".
But I think in a well-functioning democracy, when a majority of all voters are clearly calling for a presidents resignation (think mass protests), that should mean the end of a presidency. Whether by legal means, or by a president "voluntarily" stepping down.
I won't rehash what others have said.
An impeachment is a trial.
In Australia we are ruled by a Governor General sitting in the Executive Council with some ministers advising. That's it.
We have an entire parallel unofficial government structure that really rules us. That is prime minister and ministers sitting in cabinet. But there is no such official thing as a cabinet.
The GG has to take advice from the ministers sitting in the executive council. Yet any decision making powers ministers have are delegated from the GG.
A government is formed by the person believed to be able to pass supply in parliament. The outgoing Prime Minister will advise the GG who he believes that is.
The person will be asked can you pass supply. If yes they will be sworn in. Note the election counting is still going on and the election is days away from being declared.
Motions of confidence/no confidence and bills of supply (depends who moves them) are testing the ability of the government to control parliament. Not passing supply or have the parliament's confidence will mean the government will resign.
It is not a trial. It's a test of numbers.
It is nearly always bought on as a piece of political drama by the opposition, in the hope of getting on the nightly news. It rarely is of any actual importance. It is a debating tactic.
Impeachment is a slow, protracted process that requires sustained effort and support. A no confidence motion is a single vote.
Impeachment is therefore much less attractive. Even if it works it takes so long as to often be ineffective, and can easily backfire if it turns out that the impeached politician is innocent or they manage to gain public support. Clinton is a good example, most Republicans involved ended up regretting the decision to start failed impeachment procedures.
A vote of no confidence is much quicker and once won puts the ball in the government's court, forcing them to deal with the fall-out and placing the blame for anything that happens subsequently with them. It also only requires winning a single vote on a single day, with no evidence or enquiry required, so the bar to success is much lower.
With respect to the United States, impeachment is meant to remove officials for reasons of gross misconduct (treason, bribery, and other high crimes and misdemeanors), rather than a simple inability to govern (in the sense of not being able to muster votes).
A recent episode of the podcast All The President's Lawyers talked about the history of impeachment in the US, and how the founders would likely be somewhat surprised that it hasn't been used more often. The modern thinking is that impeachment is reserved for offenses that count as actual crimes (such as perjury and obstruction of justice), but that hasn't always been the case. Judge John Pickering was impeached in 1803 for, among other reasons, being drunk and abusive on the bench.
However, when it comes to Presidential impeachments, it's probably a good thing that it hasn't been used more often. It's not something you want to become a norm.