The phenomenon is Donald Trump and this is Steyn's commentary on a rally he attended for Trump in Vermont (Mark calls it "Berniestan"), and his candidacy in general.
Steyn praises Trump for his spontaneity, humor, and folksiness. Despite being known as very rich, Trump gets the attendees to identify with him, and not in the phony customary way attempted by most politicians (think Hillary).
The piece is, as usual, seeded with a number of examples of Steyn humor, but I shall select but one to illustrate this:
"If the national GOP is a vehicle for ensuring that John Boehner, Mitch McConnell and Paul Ryan have a car and driver and a Gulf emir-sized retinue, then it's very effective. If it's a vehicle for advancing conservative principles, then it's a rusted-up lemon on cinder blocks. At an event with Newt Gingrich about a decade ago, one of my neighbors asked why the Republicans were so ineffectual. Newt said it was because they're still getting used to being the majority party. Somebody responded, "So the Iraqis are supposed to get the hang of self-government after six months, but the Republican Party still can't manage it after ten years?"
Recommended:
http://www.steynonline.com/7408/notes-on-a-phenomenon