Spending on the Aroostook County election battle between Democratic Senate President Troy Jackson and Republican state Rep. Sue Bernard has now topped $1 million, more than twice what is being spent on any other state legislative race.

Most of that – $808,226 – is being spent to reelect Jackson. Only a fraction of it was raised by Jackson himself; most of it, or $748,000, was spent by the party or outside groups to pay for ads touting the perks of Jackson’s leadership position or mailers targeting his opponent.

Maine Senate President Troy Jackson Michael G. Seamans/Morning Sentinel

In contrast, outside groups have spent just $183,385 to elect Bernard, a conservative state representative from Caribou well known as a former TV anchor and a spokeswoman for Maine’s Catholic Diocese. Some of these independent-funded ads have drawn sharp criticism.

The majority of the $931,623 that outside groups have poured into the District 1 Senate race has come in the last two weeks of the campaign. On Oct. 10, outside groups had spent just $263,344 on the race, which was a sum large enough to raise eyebrows and fuel more spending.

The vast majority of this year’s spending is aimed at influencing elections in the Maine Senate, where Democrats hold 22 of the 35 seats. That suggests both parties see control of the upper chamber as the most likely to flip from Democrats to Republicans.

Outside groups are funneling their cash to elect Senate Democrats over Senate Republicans by nearly a 5-to-1 margin, according to the latest campaign finance reports. In total, pro-Democratic groups have spent almost $3.3 million to influence these Senate rates.

The other contests rounding out the top-five races drawing the biggest outside spending include:

• District 20 (Auburn) Eric Brakey (R) vs. Bettyann Sheats (D) Total: $471,703

• District 14 (Gardiner-Hallowell) Jeff Hanley (R) vs. Craig Hickman (D) Total: $419,328

• District 11 (Waldo County) Glenn “Chip” Curry (D) vs. MaryAnne Kinney (R) Total: $415,471

• District 13 (Boothbay-Wiscasset) Cameron Reny (D) vs. Abden Simmons (R) Total: $316,940

In each of these top-dollar races, Democrats reaped more benefit from the outside spending than Republicans. In some cases, like the District 20 race, the expenditure differential was profound – outside groups spent almost nine times more helping Sheats than Brakey.

The groups trying to sway legislative contests can spend money directly to influence a race, but can’t coordinate with individual candidates, who are raising and spending much smaller amounts of money to run their own campaigns.

Sue Bernard, R-Caribou Joe Phelan/Kennebec Journal

The Maine Senate has flipped four times in the last six elections. Republicans must hold their 13 seats and flip five Democratic seats to take control. They have a slight edge when it comes to open seats: 10 incumbents – six Democrats and four Republicans – can’t run again due to term limits.

If successful, Democrats would maintain the ability to elect constitutional officers, including the secretary of state and attorney general. If Gov. Janet Mills wins reelection over Republican Paul LePage, the party would have the power to set policies on abortion, taxes, health care and energy.

The party that wins one or both chambers but loses the Blaine House could deadlock the next governor.

While the battle for the Legislature is intense, and is believed to have broken unofficial state spending records for a single legislative race and total legislative spending, it still isn’t drawing the kind of dollars being spent to sway voters in this year’s gubernatorial race.