Seth Stevenson at Slate with a great peek behind the curtain covering Trump on the trail. This can't end well:

“How many times can you write that the same statement is untrue?” mused one reporter. “At some point, the lie stops being news.” And debunking a claim doesn’t stop Trump from making it again.

And:

It’s also hard to know who the fact-checking is for. At this point, anyone who hates Trump has ample evidence he’s a liar. And anyone who loves Trump doesn’t care.