STATE HOUSE, BOSTON, DEC. 20, 2010... As leaders on Beacon Hill anxiously awaited the Tuesday release of 2010 Census population totals, those soon to be involved in the complicated and likely contentious process of carving up the state’s political districts took stock of what awaits and the debates, both political and practical, that loom.

The U.S. Census Bureau plans on Tuesday to release national and state population figures providing key data to states charged with redrawing the boundaries of Congressional districts, including ten in Massachusetts that are all held by Democrats.

Massachusetts is widely expected to lose one seat based on its own population trends and more rapid growth in other parts of the country, joining the likes of New York, New Jersey, Ohio, Iowa, Pennsylvania, Michigan, Illinois, Minnesota and Louisiana.

In addition to the expected loss of clout on Capitol Hill, the Census results could impact the level of federal aid the state receives through programs that pay based on per capita formulas. It will also require the redrawing of state House and Senate district boundaries.

Gov. Deval Patrick on Monday said that he was “concerned” about the potential loss of a Congressional seat despite the state’s aggressive efforts to maximize its Census count through outreach to minority communities and college campuses.

“I’m concerned but I don’t have any information,” Patrick said.

Though Secretary of State William Galvin has said he’s “hopeful” that a thorough Census count, combined with less thorough counts in other states, could avert the loss of a Congressional seat, other officials were more resigned to that fate.

“All the experts we’ve consulted with over the past couple years have been expecting the loss of a Congressional seat. We’d love a little miracle, but we’re not expecting it,” said Sen. Stanley Rosenberg, an Amherst Democrat who will co-chair the Legislature’s redistricting committee in charge of drawing the new boundaries.

Rosenberg has been through this process before, serving in the same role in 2001 after the last Census when Massachusetts managed to hang on to all 10 seats when population grew by 5.5 percent between 1990 and 2000.

Rosenberg and Rep. Michael Moran, of Boston, are both slated to be tapped as the chairmen of the soon-to-be formed redistricting committee that will be named sometime in January by House Speaker Robert DeLeo and Senate President Therese Murray after the new legislators take office.

In 2000, the committee consisted of eight senators and 34 House members.

Rosenberg said that the committee has already hired staff, installed computer equipment and signed contracts with several specialists they will rely upon for technical assistance throughout the process. The committee intends to launch a website with history, rules, redistricting principles and legal cases that will inform the process, and will hold public hearings throughout the state to seek input.

House Minority Leader Brad Jones, who was thwarted in 2009 and again in 2010 in his efforts to create an independent redistricting commission, said he plans to take a lead role on the Republican side of the debate, perhaps even serving on the committee himself.

Noting Galvin’s decision to recently give voice to the benefits of an independent, non-partisan commission, Jones said he has been attending information sessions and sending staff to training seminars to prepare for the effort.

Should the state lose a seat in Congress as expected, each of the nine remaining districts will have to absorb an average of about 72,000 people, depending also upon population shifts within the state and growth rates within existing districts.

U.S. Reps. John Olver and Richard Neal, the two Congressmen from western Massachusetts, have both come out early to declare their intentions to run again in 2012, perhaps seeking to forestall any attempt to consolidate districts in the western half of the state.

The possibility that U.S. Rep. Michael Capuano will run again for the U.S. Senate against Sen. Scott Brown has also stoked talk of consolidating Boston into one district that could potentially be a majority-minority district under the Voting Rights Act.

The average Congressional district after the 2000 Census had almost 647,000 people. Rosenberg said it was unclear whether the Census Bureau would release detailed state population numbers by city and town Tuesday, or just the statewide figure.

The factors that go into drawing districts can be complicated and sometimes contradictory. For instance, lawmakers can craft districts to include “communities of interest” that share a school district or water district, but courts have also ruled that they can break up those same clusters in order to respect “tradition” for where a city or town has historically resided.

“It’s really a balancing act,” Rosenberg said.

At the Congressional level, map drawers are given no leeway for deviations in populations, authorized to draw district lines that split streets and even households if necessary to meet population targets. At the state level, however, Rosenberg said court rulings have established a plus-or-minus 5 percent standard for local House and Senate districts.

Lawmakers cannot intentionally break up minority communities into separate districts that would prevent someone of color from being elected to office, but are also prevented from “torturing” or going out of their way to “pack” districts with minority voters.

The districts are supposed to be “geographically compact and contiguous,” “competitive,” and “incumbent blind,” according to independent watchdog Common Cause.

During the state’s last foray into redistricting, Rosenberg said there was not a sufficient minority population in Boston to create a majority-minority state Senate district, but they were able to craft a “minority-influence” district that is now held by Sen. Sonia Chang-Diaz, and a “fair fight district” that led to former state Sen. Jarrett Barrios being elected the first Latino senator in the state.

“Boston may have grown slightly faster than the average of the rest of the state which could mean, depending on who they are and where they are, there might be the capacity to create a majority-minority district,” Rosenberg said.

Rosenberg said it was too early to state goals for the Congressional redistricting process, but acknowledged a number of potential scenarios and areas of debate that will get scrutiny. He said some will push to see district lines in the western part of the state drawn east-to-west instead of north-to-south.

He also noted that five of the 10 current Congressmen – including U.S. Rep.-elect William Keating – live “within 10 miles of the State House.”

“I know we have a small state, but that’s still quite a bit of concentration,” Rosenberg said.

Rep.-elect Daniel Winslow, a Republican of Norfolk, had been leading the early redistricting efforts for the Massachusetts Republican Party, but said that after winning his election, he plans to transition to working with a newly-forming “non-partisan citizens” group, whose formation will be announced shortly.

Winslow said he is eager to see the results of the 2010 Census and will be watching to see if states that lose seats are “dominated by one political party.”

“Is this people voting with their feet against high-tax, anti-job states?” Winslow said. “I believe that if we do nothing we will continue down the path of being a Congressional cipher. This is a trend, and it’s directly related to the high cost of living, cost of housing and the lack of economic opportunity for young people.”

Judging from preliminary Census estimates, Winslow said population growth in Boston among immigrant groups could present the opportunity for the first time to create a majority-minority Congressional district centered on the city.

“The Congressional districts in Boston currently fracture the minority population, which I believe is a violation of the national Voting Rights Act,” Winslow said.

He also said it would be incumbent upon the map-makers to eliminate districts like the 4th district that snakes its way from New Bedford to Newton, citing the requirement that districts be compact.

“Anyone that looks at Barney Frank’s district, and I’m not trying to single out Barney, but you will know at a glance that is not the case. Barney Frank’s district would make Gov. (Elbridge) Gerry blush,” said Winslow, referencing the namesake of the term gerrymandering, meaning to craft district to favors political parties or candidates.