One hundred days from today — November 7, 2012 — the national commentariat will either be analyzing why Americans chose eight years of President Barack Obama, or engaging in breathless speculating about President-elect Romney’s transition team. In the interim, we’ll dive in to numerous campaign controversies, from the profound to the picayune. We’ll learn the identity of Mitt Romney’s running mate, we’ll watch four debates with baited breath, and we’ll pore over polling data until our eyes glaze over. As the race stands today, it’s a total toss-up. Gallup’s daily tracker shows the race tied at 46 apiece, with Rasmussen giving Romney a two-point edge. The latest NYT/CBS survey has Romney up by a hair, with NBC/WSJ’s pollster pegging Obama as fairly comfortably ahead. (Both polls rely on unrealistic partisan samples). With a month until the Republican National Convention in Tampa, national trends will bob up and down, but it won’t be until mid-September — when both conventions are over, and polling bounces fade — that we’ll really begin to grasp the true complexion of this race. As we impatiently await autumn’s arrival, we’ll keep an eye on President Obama’s job approval rating, perhaps the best measuring stick for his re-election prospects. But ultimately, everything will boil down to electoral college math. Karl Rove’s Wall Street Journal May column spells out the arithmetic plainly.