Funnily enough, this was the quote of the day today (2008-04-06) and in the same day I read in a book the same quote. However, in this book, the quote is quoted from Alexander Tytler, a scottish economist. Wikipedia also has this quote from him: http://en.wikipedia.org/wiki/Alexander_Tytler It would appear this quote is not by Marx, but by Tytler.

"America was founded by men who understood that the threat of domestic tyranny is as great as any threat from abroad. If we want to be worthy of their legacy, we must resist the rush toward ever-increasing state control of our society. Otherwise, our own government will become a greater threat to our freedoms than any foreign terrorist." - Ron Paul, Texas Straight Talk, May 31, 2004