Could 2017 be the most expensive campaign yet for the Los Angeles Unified School Board? It's possible if the early pace of outside spending in the race keeps up.

With less than one month to go before the March primary, outside groups have already spent $2.9 million on television, political mailers, canvassing and phone-banking in hopes of swaying the outcome in the race for three L.A. school board seats.

At this point in 2013 — in a race that ended up being the most expensive L.A. school board campaign in at least the last 15 years — only $1.6 million in "independent expenditures" had been reported.

By law, independent expenditures cannot be made in coordination with any one candidate's campaign. Still, this money has come to define L.A. school board races, outstripping contributions to individual candidates' campaigns most years.

The main difference between 2013 and this year: a marked increase in early independent expenditures to oppose candidates.

By this stage in 2013, groups affiliated with the United Teachers Los Angeles teachers union had spent more than $160,000 to oppose two candidates with pro-charter school leanings — and pro-charter groups had spent nothing to oppose any candidate.

This year, that storyline has inverted. Outside groups have already spent more than $1.2 million to oppose candidates; most of which — a little more than $1 million — has come from pro-charter school groups to oppose incumbent board president Steve Zimmer, including $682,000 in television ads.