The world’s rival crude-oil benchmarks have been galloping apart since the beginning of the year. It’s about time to rein them in.

The U.S. price most Americans recognize — the futures for the high-quality blend of crude-oil traded on the New York Mercantile Exchange — historically has traded within a dollar or two of its European counterpart, Brent crude, on ICE Futures Europe.

Until this year.

Starting in January, the oil prices’ paths have diverged for a duration and by a magnitude without precedent. The so-called spread between Nymex crude — which is still widely referred to as WTI for the West Texas Intermediate blend that used to gush out of the mid-continent — and Brent hit a record of almost $27 in early September