Democrats have hit back at veteran GOP Sen. Chuck Grassley for calling President Barack Obama “stupid” in a weekend Twitter message. “Ive know @ChuckGrassley a long time. I am saddened he would embarrass himself like today with his comments about the President,” Obama's campaign manager, Jim Messina, tweeted. Meanwhile White House senior adviser David Axelrod said, “Heads up, Sen. Grassley. I think a 6-year-old hijacked your account and is sending out foolish Tweets just to embarrass you!” ABC News reported. But the senior senator from Iowa was unrepentant. “In his Tweet on Saturday, Sen. Grassley said that it doesn’t speak...