Save a niche in local political history if the Los Angeles school system passes a parcel tax June 8.

Convention holds that there's no logical way Measure E can achieve the two-thirds majority it needs. Backers maintain hope, insisting that, above all, the cause is just and the emergency dire.

Measure E would raise $92.5 million annually over four years for the Los Angeles Unified School District through a tax of a flat $100 per parcel. The money would undo some cutbacks made to offset a $640-million deficit for next year and beyond.

The district has a tall political hill to climb. Relatively low turnout in the primary is expected to trend conservative, older and Republican — all bad for L.A. Unified, experts say. Worse still, the Republican tickets for governor and U.S. senator are hotly contested; the corresponding Democratic races are uncompetitive.

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And parcel taxes have fared best in smaller, prosperous enclaves such as San Marino and South