It's starting to look like 1948 all over again. Mark Twain observed that while history doesn't repeat itself, it often rhymes. The 2012 presidential campaign is now rhyming with that of 1948 in iambic trimeter - the poetic form tragedians of Ancient Greece such as Aeschylus and Sophocles used to best express portending doom. So let's revisit that extraordinary yesteryear of 1948, resulting in the most famous upset in American politics - Democrat Harry Truman defeating Republican Tom Dewey - and see how we can avoid a similar outcome by using it to our advantage. In 1944, FDR was running...