Posted by Nicholas Beaudrot of Electoral Math
Like Hilzoy, I think that the Clinton impeachment has raised the bar for what ought to be an impeachable offense. Politically, if the opposition party calls for every President's head, we will have turned what ought to have been a very solemn process into nothing more than a political tool. From a policy perspective, the impeachment process will stall all other legislative and policy work for at least two years of each Presidency, which might be a good while reactionaries are in office, but bad when the reactionaries hold Congress and decide to investigate a reality-based President.
Update: Several people have said that the Clinton impeachment lowers the bar. Others (see e.g. Lindsay) say that at the very least it did nothing to raise the bar. Upon reflection, this is of course correct; if the Clinton impeachment was improper, it should be ignored when examining the prospects of future impeachments.