The second impossible thing that could happen is a vast expansion of the Republican primary electorate — and general election turnout. Sparked, at least initially, but not necessarily permanently, by Donald Trump.

The New York Times reported last week that other Republican candidates’ strategists discount Trump’s current poll leads on the grounds that the polls “rely on feedback from many Republicans who are unlikely to vote” because they aren’t registered Republicans or haven’t voted in past primaries.

It’s true that past Republican turnout has been low. In 2008, 37 million Americans voted in Democratic primaries and caucuses and only 21 million voted in Republican contests. Hillary Clinton, while losing the nomination, got almost as many votes as the three leading Republicans put together.

Similarly, many analysts blame Mitt Romney’s 2012 loss on conservatives staying home. Barack Obama got 3.5 million fewer votes in 2012 than in 2008. Usually incumbents who drop that far lose. But Romney got only 1 million more votes than John McCain in 2008.

Even in a period of close partisan divisions, when one party’s turnout increases it can win decisively. Democratic total votes increased 10.5 million when Obama won in 2008. Republican total votes increased 11.5 million when George W. Bush was re-elected in 2004.