A consortium of oil-producing countries has taken more than a million barrels a day off the market — and that’s the least of the problems plaguing American gasoline prices. Across the U.S., regular gas averaged $2.77 a gallon, up 7 cents on the week and 29 cents on the month, according to GasBuddy. Last year, gas prices topped out at $2.98 at the outset of Memorial Day weekend. Oil prices are climbing, but that only accounts for about one-quarter of the recently higher gas prices American drivers have been facing. A bigger issue is that this is around the time...