AUGUSTA, Maine — Moving a scant 4,300 voters — less than one half of 1 percent of Maine’s population — from one congressional district to another seems simple on the surface.

But as easy as it sounds, there remains one significant complicating factor: politics.

“We’re dealing with a relatively small imbalance and that should be an easy fix, but anytime politics gets involved, it’s going to get messy,” said Mark Brewer, a political scientist at the University of Maine.

Redrawing those important political lines is now the task of a bipartisan commission of seven Republicans, seven Democrats and one independent moderator. The group recently began the process of redistricting, something that is required once every decade to coincide with updated U.S. Census data.

Republicans and Democrats have vowed to keep the conversation civil during the redistricting debate, which will heat up next month when the 15-member panel meets again.

Longtime lawmaker John Martin, D-Eagle Lake, has participated in redistricting in the past and has been appointed to the commission this year.

“It has been [political] in the past, but I don’t think we need to make it that way,” Martin said. “There are some easy solutions out there.”

Rep. Kenneth Fredette, R-Newport, one of several first-time legislators named to the redistricting commission, agreed that politics should be left at the door.

“We want to come up with a plan that has overwhelming [legislative] support,” he said.

Still, when the doors are closed and ideas are put on the table, the discussion could take on a life of its own.

What is redistricting?

Maine has two Congressional districts.

The 1st District is made up largely of the populated southern Maine counties around Portland, the state’s largest city. The 2nd District encompasses the balance of Maine and, geographically speaking, is one of the the largest Congressional districts on the East Coast.

Steadily over the last several decades, the state’s population has shifted south. The 2010 census numbers continued that trend. Currently, 668,515 people live in the 1st District, while 659,848 live in the 2nd.

That means in order to make the populations as equal as possible, the line separating the two districts needs to move a little bit.

The existing line is as jagged as Maine’s coast.

It starts at the New Hampshire border near Parsonsfield, then rises north around Bridgton before dipping south of Oxford. The line continues south, putting Lewiston and Auburn in the 2nd District, but keeping Bath and Brunswick in the 1st.

Then things get a little confusing.

The line travels around Augusta and Waterville, separating the two Kennebec County communities. There is a funny elbow encompassing the town of Albion where the 1st District juts into the 2nd. Then the line gradually falls south following the Knox County boundary to Camden.

So, what does this all mean politically?

“The 1st district certainly is creeping closer to a one-party district, almost a lock Democratic district,” Brewer explained. “As that happens, individuals in those districts who are in the opposite party become disenfranchised.”

So the thought, at least for Republicans, is likely to be: How can we make both more competitive?

If that’s the case, Brewer said, the focus could be on the 2nd District.

“I’m not sure the [Republicans] can unseat Michaud, but he can’t hold that seat forever,” Brewer said.

Why is this happening now?

In past decades, the process of redistricting Maine started much later, but a lawsuit filed earlier this year led a federal judge to change the timeline.

The suit, filed by Cape Elizabeth residents William DeSena and Sandra Dunham, both Republicans, argues that the process should begin sooner because votes are diluted if the congressional district races are based on outdated census data.

So, the commission’s task hasn’t changed, but there is much less time now to redraw the lines. Recommendations must be submitted to the Legislature by the end of August. Lawmakers will then meet in special session in mid-to-late September with an action deadline of Sept. 30.

If lawmakers can’t reach an agreement, it would go to the Maine Supreme Judicial Court, which would have until Nov. 15 to finish the reapportionment.

If a deal still isn’t reached, a panel of federal judges would take over and make a decision by Jan. 1, 2012.

Reps. Martin and Fredette both said they hope court intervention is not necessary.

Who is deciding this?

Republicans chosen earlier this month to serve on the commission were: Fredette, Reps. Les Fossell of Alna and Richard Cebra of Naples, and Sens. Debra Plowman of Hampden and Rodney Whittemore of Skowhegan.

Josh Tardy, a former lawmaker and lawyer from Newport, was picked as the public representative, and Dan Billings, chief counsel for Gov. Paul LePage, will represent the Maine Republican Party.

For Democrats, Martin will be joined by Reps. Joan Welsh of Rockport and Henry Beck of Waterville along with Sens. Philip Bartlett of Gorham and Seth Goodall of Richmond.

The Democrats’ public representative will be Cathy Newell, chairwoman of the Oxford County Democrats, and the Maine Democratic Party representative is Dick Grandmaison of Lewiston.

In the middle of all those Ds and Rs is Michael Friedman, a Bangor attorney and former chairman of the Maine Ethics Commission. Most agree he’s as independent as they come.

Although the commission is bipartisan, this is the first time in decades that Republicans have controlled the House and Senate, a fact that has made some Democrats nervous.

“We have set a precedent of putting fairness and transparency before partisan politics,” House Democratic Leader Emily Cain said shortly after the court order last month. “Democrats hope and expect that this body will continue to uphold this precedent no matter who holds the reins.”

How will it work?

There are a few ground rules.

The line has to be contiguous. The commission cannot divide a city or town but they can split a county if needed. Some ideas that have been floated include:

• Dividing the state east and west instead of the traditional north and south divide, a radical shift that may not be feasible because of the short timeline.

• Moving some coastal islands, including Rep. Chellie Pingree’s hometown of North Haven, into the 2nd District.

Moving North Haven would not matter much because Pingree could simply move her primary residence to Portland, where she also owns a home. Also, although it’s tradition, a House member is not required to live in his or her district.

Willy Ritch, a spokeswoman for Congresswoman Pingree, said Maine has a history of redrawing lines in a nonpartisan way and Pingree hopes that continues.

“Moving her hometown doesn’t make sense and seems partisan and personal,” Ritch said.

Michaud’s spokesman Ed Gilman said the Congressman is hopeful that the bipartisan approach yields a fair result.

Although it’s not explicitly required, past redistricting plans have been voted on by at least two-thirds of the Legislature, which mirrors the requirement for legislative redistricting. That’s when the state redraws lines for House and Senate seats and that won’t happen until 2013.

Redistricting likely will affect only a limited number of voters, but it could drastically change the political landscape for those voters. The last time this process was undertaken, for instance, the city of Waterville moved from the 1st District to the 2nd District. Knox County, which had been suggested to moved into the 2nd District, stayed in the 1st.

Some political watchers are curious to see whether the current redistricting debate is Maine’s last.

Since the House of Representatives is divided by population, if Maine’s population stays stagnant or drops in 10 years and other states see big population gains during the same time, Maine could become a one-district state. That would remove any need for redistricting — and the statewide debate that follows — but also would limit Maine’s power in Congress.