AUGUSTA — Many of this year’s close and expensive races for the Maine Legislature look a lot like they did two years ago, with party control of the chambers hanging in the balance.

After the passage of the filing deadline for party candidates last week, the races in Maine’s 186 legislative districts have started to take shape, although unenrolled candidates have more time to file. There are some primaries to be decided between now and November, but in many districts, the final matchups are set.

The Kennebec Journal and Morning Sentinel compiled a list of the 10 most interesting races, likely to attract lots of money and a nip-and-tuck vote difference. Our choice for the top race, for a Senate district in Bangor and Hermon, was home to the state’s most expensive race in 2012.

The list is heavy on rematches, with one of Augusta’s most famed powerbrokers plotting a return to the State House from the St. John Valley after a 2012 upset.

1. Incumbent Sen. Geoff Gratwick, D-Bangor, vs. Cary Weston, R-Bangor

The Bangor area brought Maine the most expensive legislative race in state history in 2012 with more than $450,000 in outside spending, most of it spent to attack the candidates. Bangor and Hermon residents could see just as much spending this year. Gratwick, a doctor and freshman legislator, will face Weston, a marketer with two big pluses: He’s an ex-Bangor mayor with no legislative record for Democrats to attack.

2. Incumbent Rep. Mike Nadeau, R-Fort Kent, vs. John Martin, D-Eagle Lake

In 2012, Martin, a legislator for 46 years and perhaps Maine’s most powerful lawmaker ever, was shockingly beaten by Nadeau, who hasn’t been very visible in Augusta. However, Martin has run into business troubles, including bankruptcy, in recent years. The campaign may show that voters in western Aroostook County have finally tired of the ex-House speaker, known to many as the Earl of Eagle Lake.

3. Incumbent Sen. James Boyle, D-Gorham, vs. Rep. Amy Volk, R-Scarborough

The freshman incumbent Boyle won easily in 2012 in a solidly blue district. But Volk, who could have served two more terms in the House, has two things that may give her an edge: She has been out in front on high-profile issues, notably by sponsoring a bill to aid victims of sex trafficking, and the Senate district got more conservative in the redistricting process last year, swapping part of Westbrook for Buxton.

4. Incumbent Sen. Chris Johnson, D-Somerville, vs. Les Fossel, R-Alna

This is a rematch of a messy 2012 race in which outside groups poured more than $75,000 just to attack Fossel. That was twice the total spent against Johnson, who won the seat comprising most of Lincoln County and other towns by less than 200 votes over the former state representative, the third time Fossel lost a Senate campaign after a recount.

5. Incumbent Sen. John Cleveland, D-Auburn, vs. Eric Brakey, R-New Gloucester

Cleveland, a quiet but influential senator who helped negotiate the omnibus energy reform bill passed last year, will have his hands full with Brakey, a 25-year-old libertarian who raised $21,000 by January’s end — more at that point than any candidate in Maine’s history. He’s a recent transplant to the district, which goes west to Poland.

6. Incumbent Sen. Brian Langley, R-Ellsworth, vs. Ted Koffman, D-Bar Harbor

Langley could have shielded himself from future Democratic attacks by voting yes on Medicaid expansion, but he voted against it after some identified him as a potential swing vote. He’s now faced by Koffman, an ex-legislator and executive director of the Maine Audubon Society. Now Langley, who won his seat representing most of Hancock County narrowly over a lesser-known hopeful in 2012, could be in danger.

7. Incumbent Rep. Deb Sanderson, R-Chelsea, vs. Joel Pitcher, D-Jefferson

Aside from Gov. Paul LePage, nobody has been more vocal in the fight against Medicaid expansion than Sanderson, the top Republican on the Legislature’s health committee who won a tight 2012 race over a former legislator. Pitcher, a Bath Iron Works ship-fitter and union organizer, probably isn’t as well-known in the rural district. But Democrats may spend a lot to get rid of Sanderson.

8. Incumbent Sen. Garrett Mason, R-Lisbon Falls, vs. Guy Desjardins, D-Sabattus

Mason, running a third time to represent towns near Lewiston, won his 2012 election by just 28 votes. His opponent then wasn’t as well-known as Desjardins, who is ending his second term as Androscoggin County sheriff after a long career in that office. He has been vocal on many issues intersecting with state policy, including jails.

9. Incumbent Rep. Joshua Plante, D-Berwick, vs. Beth O’Connor, R-Berwick

Plante, a young supermarket manager, beat O’Connor, then an incumbent, by 143 votes in 2012. She has been relevant recently as head of Maine Taxpayers United, a conservative group that has lobbied lawmakers to vote against Medicaid expansion. Well-known but polarizing even to some in her party, she’ll be as open as anyone to Democratic attacks on the Medicaid expansion front.

10. Frances Head, R-Bethel, vs. Callie Pecunies, D-Albany Township

This House seat, to be vacated by Rep. Jarrod Crockett, R-Bethel, could be a pickup for Democrats in a conservative stronghold where he won 68 percent of votes in 2010. The two newcomers are in the real estate business in western Oxford County, running to represent a large, sparse district that goes from Stow in the south all the way to Franklin County’s Canada border. Democrats are excited about Pecunies, a 2014 graduate of Emerge Maine, a group that readies Democratic women for office.

Michael Shepherd — 370-7652mshepherd@centralmaine.comTwitter: @mikeshepherdme