It's the BS refuter you have to overwhelm. We knew Trump was full of shit. But he can tell so many lies in 5 minutes it takes hours to refute it all.

Every speech of his is a Gish Gallop. See here for an explanation:
That Trump casually lies at the podium almost as often as he breathes is a well-documented claim leveled at him by traditional and new media alike. But actually unpacking all those lies in one cable news segment, in the confines of a debate, or in a single online post is a Herculean task. Take a look at this Huffington Post piece, which does a fabulous job of listing a few of the whoppers in Trump’s convention speech and summarizing the corrections—just as an example:
Trump said after Clinton’s four years as secretary of state, “Iran is on the path to nuclear weapons.” But Iran was already on a path to acquiring nuclear weapons. At issue is whether the nuclear deal will prevent Iran, as intended, from becoming a nuclear power.
What follows in the article is several meaty grafs on Iran’s actual history in pursuing nukes, spanning several White House administrations. This led to the Iranian nuclear agreement last year, and why it’s arguably in the world’s interests. But to hear Trump tell it, it all happened under Obama/Clinton through sheer negligence, and we even paid Iran billions of dollars in bribe money to sign the deal! The nod-nod wink-wink conspiratorial implication is that Clinton and Obama are in cahoots with Iran. HuffPo did a fine job reviewing all that in a concise manner, but it would be difficult to squeeze it all into a debate or a soundbite, even for someone who is well prepared. Throw in a dozen more similar convoluted whoppers, and the constraints of cable news or a debate format would make correcting even a fraction of them impossible.