Boston — With maps unfurled, crayons and calculators in hand, state lawmakers across the United States are tackling none-too-enthusiastically one of the decade's toughest assignments - legislative redistricting.
But it is increasingly uncertain how successful they will be with the complex and often politically sensitive projects, which may have far-reaching impact.
The challenge is even more difficult since in most instances it is the senators and representatives themselves - those who stand to gain or lose most - who are responsible for redrawing districts to meet ''one-man, one-vote'' standards.
While redistricting plans, based on the 1980 federal census figures, have gained passage in 30 states within the past nine months, at least one has been struck down and several others face court challenges.
And at this point there is much to suggest that judges, who first invaded the legislative districting political thicket less than two decades ago, again will have a lot to say during the current round of state carving.
There is considerable disagreement among experts, however, as to whether court involvement over the coming months will be as extensive as during the early 1970s, when judges played a role in districting of one or both legislative chambers in 18 states.
Districting-related suits are pending or threatened in 15 states - Arkansas, California, Connecticut, Illinois, Indiana, Missouri, North Carolina, North Dakota, Ohio, Pennsylvania, South Carolina, South Dakota, Texas, Washington, and Wyoming.
And disputes in several others, including Montana, Oregon, and Virginia, have been resolved.
At issue in the wave of litigation are questions on whether newly created elective territories vary too greatly in population, are sufficiently compact, are ''gerrymandered'' for unfair partisan advantage, or are shaped to dilute the political strength of minorities.
In California, Democratic lawmakers aren't seeking to overturn the legislative districting they enacted earlier this fall, but they are trying to block a GOP-spurred initiative petition to place the question of the repeal on next June's statewide ballot.
GOP foes of the redistricting contend that it is blatantly partisan and designed to increase the opposition's legislative control. This is despite the fact that on the basis of population, the newly crafted assembly and senate districts appear to be in order.
Although the US Supreme Court, from the time of its landmark ''one-man, one-vote'' decision of 1964, has never spelled out exactly how great a diversity of population among legislative districts is acceptable, a 1973 ruling by the justices made it clear that when the deviation is less than 10 percent, the burden of proof of inequity is on the challenger.
Since then, federal and state courts, with few exceptions, have let stand legislative redistricting measures in which the maximum population deviation was 10 percent or less.
The newly crafted California state senatorial districts have a top spread of 4.6 percent in population and the assembly districts a maximum variant - from largest to smallest - of 3.6 percent.
Several of the other states which have redistricted in recent weeks or months have a considerably greater population spread among their new lawmaker territories in one or both legislative bodies, notes Andrea Wollack of the Denver-based National Conference on State Legislatures.
Wyoming's challenged legislative districts, for example, have a population range of 63.7 percent for the senate and 89.4 percent in the house. These extremes result in large part from not splitting up counties.
Other newly shaped legislative chambers with a maximum variant - from largest to least populous district - in excess of 10 percent are the Hawaii senate, with 43.18 percent; Tennessee senate, 31.4 percent; North Carolina senate, 22.7 percent; Indiana house, 19.93 percent; Hawaii house, 16.02 percent; and the North Carolina house, 15.6 percent.
Of the states with one or more redefined districts with wide discrepencies in populations, only in Hawaii was the project outside lawmaker hands. That state's special redistricting commission, provided by its constitution, chose not to split islands to achieve population parity.
Newly crafted lawmaking districts coming closest to the ''one-man, one-vote'' ideal are in the Iowa senate, with a maximum population spread of 0.71 percent, and the Illinois senate, 1.59.
Others which have achieved a deviation of less than 2 percent are the Tennessee house, 1.66 percent; the Iowa house, 1.78; Texas senate, 1.82 percent; the Pennsylvania senate, 1.93 percent and the Illinois house, 1.97 percent.
Even some of this districting, however, is being challenged. In Pennsylvania, for instance, a litigation initiated by Common Cause, which has marked improved districting as one of its main goals, alleges greater population equity could be achieved.
Lawmaker districting measures in both North Carolina and South Carolina are being fought by the National Association for the Advancement of Colored People on the grounds that blacks will be deprived unnecessarily of potential representation in one or both legislative chambers.
In Virginia, where earlier this fall a federal court struck down a newly enacted legislative districting measure on the grounds it failed to meet ''one-man, one-vote'' standards, Republican Gov. John Dalton recently vetoed a revised plan for the house of delegates. He charged that although the maximum variant had been reduced from more than 20 percent to 12.9 percent, it was deficient in respect to district compactness and consideration of ''community interest''.
In wiping out the original redistricting, the judges gave Virginia lawmakers until next Feb. 1 to come up with an acceptable measure, or it will do the redistricting of the 40-seat senate and 100-member house itself.
Other states which have not yet completed the realignment in either house are Arizona, Colorado, Florida, Idaho, Kentucky, Maine, Maryland, Michigan, Minnesota, Mississippi, Montana, New Mexico, New Hampshire, New York, Rhode Island, Vermont, West Virginia, and Wisconsin.
Most of them are expected to approve some kind of a measure by early spring in time for 1982 legislative campaigns. The special commission responsible for crafting new districts for Montana, however, has postponed the job, with court approval, until early 1983.
Besides Montana and Hawaii, at least six other states - Arkansas, Colorado, Michigan, Missouri, New Jersey, Pennsylvania, and Ohio - have similar panels outside the legislature to handle redistricting. And several have backup boards which take over should lawmakers miss their deadline, as happened in Illinois last summer.
Sometimes special nonlawmaker panels, too, become stalemated and courts have to step in. The new districts for the Missouri senate, for example, were fashioned by a panel of judges.
In Massachusetts, where new districting based on a mid-decade state census was completed in 1977, and Kansas, where an elective territory reshaping was completed in 1979, no legislative redistricting is scheduled.