There’s something tremendously invigorating about this. They called Lincoln “old” when he was in his 30s, a testament to his gravity. Newt feels young even though he’s about as old as Ronald Reagan when he ran in 1980. If Franklin Roosevelt was like a bottle of champagne, according to Winston Churchill, Gingrich is like a snort of helium.

His volatility makes it impossible to make any statement about him as a general-election candidate with assurance. Will he enthuse the Republican base? Yes, right up to the moment he stops enthusing it with some jarring provocation. Will he beat President Obama in the debates? Yes, right up until he makes an ill-tempered comment that washes away all his impressive knowledge and brilliant formulations. Will he be the bipartisan healer, the partisan bomb-thrower, or the post-partisan big thinker? Yes, yes, and yes.

All that is predictable about Newt is that he is unpredictable, and, irresistibly, an election that should be about President Obama and his record will become about the heat and light generated by his electric performance. That’s the way it was as speaker, too. Eventually, he wore out his welcome in epic fashion. Benjamin Franklin said any houseguest, like a fish, stinks after three days. With the public and his colleagues, Gingrich became the houseguest who would never leave.