Election Day in even-numbered years can bring a sea change to politics in Augusta because that’s when every seat in the Legislature comes up for grabs. Adding to the uncertainty of the outcome are the facts that redistricting this year has slightly altered Maine’s political landscape, and the state’s term-limit law and personal decisions not to seek re-election will remove many key incumbents from the ballot.

With less than a month before the vote, here’s a look at key factors this year:

The legislative races are important because they could embolden or handcuff whoever is elected governor. In a way, just about everything you’ve heard from the gubernatorial candidates about policy amounts to little more than pipe dreams. Without support in the Legislature, the executive branch is severely limited in what kind of initiatives it can enact. The last two years offer a prime example of what happens when a governor (Republican Paul LePage) and legislative leaders (Democrats) disagree fundamentally on how the state should be run. That scenario yielded a record number of vetoes, duelling budget plans and partisan gridlock.

The best outcome for whoever is elected governor is for his party to win two-thirds majorities in the House and Senate, which means that party could override vetoes on its own, pass emergency legislation and do pretty much as it pleases. The State House has not seen that scenario in decades — and there’s nothing to indicate that either party has a strong enough hold on Maine’s electorate to achieve such dominance this year.

Control of the Legislature has swung from Democrats, who held majorities for much of the past two decades, to Republicans in 2010 and back to Democrats in 2012. With pent-up acrimony from the past two years — and the departure of several lawmakers who played key roles in forging compromises that won enough support to avert state government paralysis — a narrow majority for the party that does not win the Blaine House could lead to more entrenched gridlock.

Majority status in the Legislature also is crucial because lawmakers choose the secretary of state, attorney general and state treasurer every two years.

The current breakdown of the Senate is 19 Democrats, 15 Republicans and one independent. In the House, it’s 88 Democrats, 57 Republicans and four independents.

The outcome of legislative races will be a surprise to just about everyone. There is little or no public polling for legislative races. In general, incumbents in local races are difficult to unseat unless they are tied to a scandal or swept out of office as part of partisan waves, as was the case when Democratic candidates rode President Barack Obama’s coattails in 2008, and Republicans who benefited by a tea party surge and backlash against Obama in 2010.

Factors that could affect this year’s legislative races are the state’s bear-baiting referendum, the open seat in the 2nd District and heightened discontent with Obama. Voters motivated to turn out for those issues could sway close legislative contests.

Geography also plays a factor, with southern Maine — especially urban areas — considered Democratic strongholds, while northern Maine has swung more solidly to the GOP in recent legislative elections.

And of course, there are times when results defy all predictions, such as two years ago, when Democratic Rep. John Martin of Eagle Lake lost his re-election bid after serving — with one brief interruption — in the Legislature since 1964, including 19 years as House speaker. Martin is on the ballot again this year against Republican Allen Michael Nadeau, the man who beat him in 2012.

In the coming month, watch where outside spending — which has increased dramatically on legislative races — is targeted to see where the parties think they can make gains.

The prevailing theory is that Republicans have a better shot at taking over the Senate than the House. Senate Democratic Leader Troy Jackson gave up his seat to run unsuccessfully in the primary for the 2nd District U.S. House seat, leaving the Aroostook County Senate seat open for a contest between Republican Peter Edgecomb of Caribou and Democrat Charles Theriault of Madawaska, both of whom previously served four terms in the House. Martin’s surprising defeat in 2012 and the rightward shift of northern Maine voters could tip what for years has been a Democratic seat to the GOP.

If past history holds form, Senate races in Bangor and Lewiston-Auburn could determine which party controls the upper chamber for the next two years.

The Bangor-area Senate seat, which is now District 9, has been one of the most hotly contested in recent elections. Incumbent first-term Democrat Geoffrey Gratwick faces a challenge from well-known Republican and former Bangor City Councilor Cary Weston. Gratwick earned unwanted attention in September when a constituent he visited while campaigning recorded him making comments critical of U.S. Rep. Mike Michaud, the Democrats’ gubernatorial candidate. Gratwick defeated one-term GOP incumbent Nichi Farnham in a 2012 contest that drew more outside campaign spending than any other in Maine history.

In Lewiston, Democratic Sen. Margaret Craven is retiring, leaving her District 21 seat open for a contest between Republican Patti Gagne and Democrat Nate Libby, a state representative first elected in 2012. Gagne is seen as the most serious GOP threat in years for what has historically been a seat Democrats could consider a lock.

Across the Androscoggin River in District 20, first-term incumbent Democrat Sen. John Cleveland of Auburn is facing a spirited — and well-financed — challenge from Republican Eric Brakey. That Senate seat has bounced back and forth between Democrats and Republicans and is perceived to be crucial to GOP efforts to win control of the Senate.

Republicans also hope to pick up a Senate seat in another district that has supported Democrats in recent elections. In what is now Senate District 30 in suburban Portland, Republican Rep. Amy Volk of Scarborough is giving up her House seat to challenge one-term Democratic Sen. James Boyle.

In District 13 in Lincoln County, Democrat Christopher Johnson faces another challenge from Republican Leslie Fossel of Alna, a former House member who lost to Johnson in 2012 by fewer than 200 votes. Since the 1990s, elections to represent Lincoln County in the Senate have — with few exceptions — been close, often requiring recounts to affirm the winner.

Democrats hold a wider margin in the House, and what little impact redistricting had is likely to consolidate their strength in more populous southern Maine. Republicans will need to count on victories in affluent coastal communities, as was the case in 2010, to score enough gains to seize a majority in the lower chamber. But what it will really come down to is the political “ground game” — which party does a better job of organizing volunteers and getting voters to the polls.

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