There are 19 states that have gone for Democrats in each of the last six elections. Those 19 states account for a total of 242 electoral votes. By contrast, there are 13 states that have voted for the Republican nominee for president in every election since 1992. Those 13 account for just 102 electoral votes.
Do a bit of simple math (the only kind I can do!) and you realize two important things:
1. The Democratic nominee this fall will, if past is prologue, start with a 140-electoral vote lead over the Republican nominee.
2. The Democratic nominee needs to win only 28 additional electoral votes to get to 270 and be elected president.
Now for some more math. If Hillary Clinton wins the 19 states that every Democratic presidential nominee has won since 1992 and Florida, she is president. Simple as that. Or if she wins the 19 states and takes Ohio, New Mexico and Nevada, she's president. Or if she wins the 19 plus Iowa, New Hampshire and Ohio. You get the idea. There are LOTS of plausible paths to 270 electoral votes for the Democratic nominee.
Now, let's do the same for Republicans. Give Donald Trump the 13 states that every GOP nominee since 1992 has won (not a total sure thing for Trump, by the way). And, give him the five states the Republican nominee has claimed in five of the last six elections. And the seven states that have voted for the Republican nominee four times since 1992. Add them all up and you get 219 electoral votes. That means Trump or Ted Cruz or whoever needs 51 more electoral votes to win. Give Trump Colorado, Florida and Nevada — three of the four swingiest states over the past six presidential races — and he still only gets to 263 electoral votes.
But wait, you say! Electoral maps can and do change! What happened from 1992 to 2012 isn't necessarily indicative of what will happen in 2016! Sort of. It is of course possible that either Trump or Cruz (or some other nominee) could expand or change the map in ways we can't imagine today. But, look at the 2012 map, which gave Mitt Romney 206 electoral votes, and tell me where Trump or Cruz pick up 64 more.
There tends to be an assumption when talking about the 2016 race and each party's prospects that the two nominees will start on a semi-even electoral playing field. That's not right. Not even close. And that reality should scare the hell out of Republicans no matter whom they nominate in Cleveland this summer.