The six-year rule is a simple arithmetic formula that dictates that an American president has run his effective course after six years in office. After that, he's pretty well useless and might as well step down. Skeptical? See Richard Nixon, Ronald Reagan, Bill Clinton, and George W. Bush.
Watching the last few years of American politics from my side of the fence, I am absolutely flabbergasted by how deeply entrenched and polarized the two parties have become. I might debate an issue I believe in, but I'll go home and consider it from both sides. My grandma was the same way.
It is outrageous that some commentators have compared President Obama to Franklin D. Roosevelt (not to mention the president's own immodest favourable comparison of himself to FDR and Lyndon Johnson and, for good measure, Abraham Lincoln).