The Republican candidates' circular firing squad now seems to be using machine guns. Whoever the eventual "last man standing" turns out to be, he may not be standing very tall or very steadily on his feet — and he may be a pushover for Barack Obama in the general election, thanks to fellow Republicans. Whether you are a Democrat, a Republican or an independent, this is a very serious and historically crucial time for the United States of America. What Mitt Romney did or did not do when he was with Bain Capital, or what Newt Gingrich did or did...