While yes, Bill Clinton was impeached for lying on a civil case -- it was a foregone conclusion BEFORE they impeached him that there was no perjury nor would he be able to be convicted.
Perjury charges are usually very difficult for prosecutors to prove because perjury is a crime of intent. This means that a defendant charged with perjury can only be found guilty if the prosecutor shows beyond a reasonable doubt that he or she intended to make the false statement under oath, or, that the witness told the lie on purpose. As such, criminal attorneys often defend their clients by arguing that the defendant did not intend to lie, or that the party believed the statement to be the truth at the time they made it.
The other thing is that it was not a Material Matter and it was not a criminal case. Having sex or not with Monica Lewinsky had beans to do with whether he forced himself on Jennifer Flowers (her own sister said she was trying to climb that pole for months).
Additionally, the Judge instructed that "sex was copulation between a man and a woman" -- so by the court rules laid out, Clinton's BJ was not considered "sex."
He was impeached, but he did not perjure himself. But he Republicans did, no numerous occasions in order to get him in the hot seat to talk about his penis.
This is just a public service announcement from people sick of us worrying about crap that doesn't matter instead of WAR CRIMES and an asshat like Bush that destroyed our economy, hired mercenaries, profited on war, approved torture, and made a fortune for oil companies and weapons dealers with a direct material benefit back to him -- and YET, we cannot investigate this unless there is a penis involved.
And we have another one of these scumbags from this rotten family in the pipe to go into office again and half the country thinks the Clintons are "more corrupt" even though they were exonerated on all 5 charges that Kenneth Starr spent 5 long years and more money than the 9.11 committee investigating.