This is the actual letter, as you'll notice nearly half of it consists of quoting the senator's question itself:
And just in case that doesn't load properly, here's the text:
Dear Senator Paul: It has come to my attention that you have now asked an additional question: "Does the President have the authority to use a weaponized drone to kill an American not engaged in combat on American soil?" The answer to that question is no.
[Update: Appearing on Fox News this afternoon, Paul says the response, as short as it was, was enough for him to drop his opposition to John Brennan's nomination. "I'm quite happy with the answer and I'm disappointed it took a month and a half and a root canal to get it," Paul said."]
Politico with the back story for those who missed it yesterday:
On Monday, Holder sent Paul another letter that was a bit less categorical. In that letter, the attorney general said: "The U.S. government has not carried out drone strikes in the United States and has no intention of doing so." However, Holder went on to say in the Monday letter that under an "extraordinary circumstance" like the Japanese attack on Pearl Harbor in 1941 or the Sept. 11, 2001 attacks, the president might need to use lethal force on U.S. soil.