Don't see Fed Chairman Warsh raising rates before the midterms, says Wharton's Jeremy Siegel

Jeremy Siegel, professor emeritus of finance at University of Pennsylvania's Wharton School of Business and WisdomTree chief economist, joins 'Squawk Box' to discuss the latest market trends, Treasury Department's debt buyback, what to expect from Fed Chairman Kevin Warsh at the Jackson Hole Economic Symposium this week, U.S.-Canada trade relations, and more.