I don't like anyone calling the President (or any other highly elected official) a "liar". Even if you think a person like that has lied on a high profile issue, it's such a perjorative term that I don't condone it.
I do find it hypocritical that some of the same people who enjoyed calling Clinton a liar now get up in arms about it when the term is used with Bush. Both guys bend the truth to their benefit in certain situations.