Right now, right-wing world is trying to drum up support for the impeachment of President Obama. Why? Why isn't really the question. As they did with Bill Clinton, they are holding an impeachment wish and are in search of a reason. With Clinton, they were actually successful, though at a distance, it is flat-out amazing (and for an amazingly stupid reason) that they were able to pull it off. Impeached for lying to Congress? Hasn't every President at some point lied to Congress?
From where I sit, Obama and just about any future president is pretty shielded from impeachment unless they do something absolutely horrible. Clinton was impeached for lying about a BJ. President George W. Bush committed offense after offense, and yet (as Speaker of the House Nancy Pelosi famously put it) impeachment was off the table. That was a huge favor by the Democrats, one that didn't sit well with actual voting Democrats. Do you think they'd sit still for an attempted impeachment of the very next Democrat to occupy the office for a very, very dubious offense?
And if the Republicans were to try such a thing, what do you think the odds would be that all of Bush's history would be dredged up for a fresh inspection? Actually, "dredging" is stretching it a bit, since you really don't have to look very hard. Take for example, the fact that Bush has admitted to torture. Take a look.