Last week was a near perfect encapsulation of the venerable American institution that is Joe Biden. We saw the bighearted, plainspoken statesman; the emotional, avuncular politician; and the cringe-inducing guy who sometimes overdoes it or just plain steps in it. On Wednesday, in Boston, the vice president pitched his “moonshot” to cure cancer to healthcare professionals, saying, “We’re on the cusp of enormous, enormous progress.”