A group of California Republicans is seeking to dump new Senate districts planned for this year's election, drawing the state Supreme Court into the once-a-decade fight over drawing political boundaries.

The legal fight Tuesday appears to have boiled down to the high court's interpretation of a 47-word passage in the California Constitution. The clause empowers residents to file legal challenges seeking to block new redistricting plans when a ballot measure after the same result is "likely to qualify."

Prominent Republican attorney Charles Bell argued that Republican interests appear to have gathered enough signatures to qualify such a ballot initiative asking voters to overturn the new maps.

Bell said that random sampling of the 711,000 signatures gathered found 72 percent of them — about 513,000 — to be valid, making it "likely" the measure will qualify for the ballot because supporters need 504,760 valid signatures.

A lawyer representing Democratic Secretary of State Debra Bowen said that the verification process is ongoing and argued that it was premature to conclude the proposed ballot will qualify for the November ballot.

The lawyer, deputy attorney general George Waters, said it was too late in the election process to develop new districts for the March and November ballots.

The secretary of state's office said after the hearing that county election officials will check the petition signatures rather than relying on random sampling to verify the measure. That process could take up to six weeks.

Meanwhile, candidates are raising money and launching campaigns for the June primary contests.

At issue is the work of the 14-member California Citizens Redistricting Commission, which created the maps.

Voters created the commission in 2010 to take away the highly politicized process of redistricting from the state Legislature. The commission members — five Republicans, five Democrats and four independents — were selected in a random process overseen by the state auditor's office. At least nine commissioners had to support the new boundaries, including at least three each from Democrats, Republicans and independents.

The state Senate districts were approved 13-1.

The lawsuit at issue was filed in October by Orange County Republican activist Julie Vandermost, who also supports the proposed ballot measure.

The new maps have created turmoil for both parties and dealt a blow to Republican efforts to maintain their waning political influence in the state.

The commission's boundaries are expected to lead to more Democratic-leaning districts because of the state's shifting demographics. Democrats have a better chance of reaching a critical two-thirds majority in the Senate than under the old maps, which would bring the party one step closer to being able to approve tax increases without Republican support.

Republicans contend the state Senate maps do not comply with the Voting Rights Act and did not meet the constitutional criteria for drawing the maps in a transparent process and in trying to keep communities together.

Bell, who represents Vandermost, urged the high court to block the new maps from going into effect and appoint an expert to draw up a new map for use this year.

The justices have several options: They could allow the temporary use of the redistricting commission's maps; use the state Senate districts that have been in place since 2001; devise an alternate plan; or create temporary Senate districts out of pairs of Assembly districts drawn by the commission.

No conclusive majority consensus emerged from the seven-member court, which has 90 days to issue a ruling. Several appeared convinced that the ballot measure would indeed qualify but were grappling with what maps to use for this year's election.

"What's this court supposed to do?" Chief Justice Tani Cantil-Sakauye mused.

The newly drawn Assembly districts are not being challenged, but a separate lawsuit by Republicans is challenging the commission's congressional districts.

The California Republican Party is helping fund the ballot initiative but is not a participant in the case before the high court.