TPM has this amusing bit from yesterday of Steve King (Asshat-Iowa) on the House floor boasting about what a bunch of liars Republican leaders are. Perhaps King was just confused or just plain stupid but here it is.

Mr. KING of Iowa. Thank you, Mr. Speaker. I can tell you that I am pleased to address you, Mr. Speaker, here on the floor of the United States House of Representatives and welcome you to this great deliberative body which becomes instantly far more deliberative than it has been over the last 4 years. This is part of it.

As I deliberate and I listened to the gentleman from Tennessee, I have to make the point that when you challenge the mendacity of the leader, or another Member, there is an opportunity to rise to a point of order, there is an opportunity to make a motion to take the gentleman's words down. However, many of the Members are off in other endeavors. I would make the point that the leader and the Speaker have established their integrity and their mendacity for years in this Congress, and I don't believe it can be effectively challenged, and those who do so actually cast aspersions on themselves for making wild accusations.

I came to this floor, though, Mr. Speaker, to talk about the weather...

And so it goes for another 30 rambling minutes of embarrassing himself and more importantly the good people of Iowa.

Here's probably the most famous usage of 'mendacity', by playwright Tennessee Williams.