The first defense witness in Minnesota's tobacco trial today underwent vigorous cross-examination from the state. Minnesota historian Hy Berman testified Minnesotans have long been aware of the health risks of smoking, but lead plaintiff attorney pointed out gaps in his research. Minnesota Public Radio's Laura McCallum reports... Tobacco companies are using their first witness to argue they aren't liable for the health care costs of smoking - as the state and Blue Cross Blue Shield claim - because smokers choose to smoke knowing the health risks. Over the past two days, history professor Hy Berman cited massive media coverage and public education in the 50s and 60s to conclude Minnesotans have been a