PHOENIX — Attorneys for the Independent Redistricting Commission are asking a federal court to dismiss what they contend is a power grab by state lawmakers.

Legal papers filed late Friday in federal court acknowledge there was a loss of power by the Legislature in 2000 when voters approved creating the commission and gave it the power to draw the lines for congressional and legislative districts. But Mary O’Grady said that does not make the system illegal.

“That was the intent,’’ she wrote.

O’Grady said the leaders of the Legislature, who are trying overturn at least part of the 2000 initiative, are “concerned more with the loss of power than the will of the people who elect its members.’’

The filing comes as Ray Bladine, the commission’s executive director, said lawmakers need to allocate at least another $1.25 million for the balance of this budget year that runs through June 30. And the big cost is defending three lawsuits against the commission, including this one filed by the Legislature.

Bladine said the request should be no surprise. He pointed out that the commission asked for an extra $2.23 million earlier this year but got just $1.12 million.

Hanging in the balance is who divides Arizona into its nine congressional districts.

Lawmakers are asking the three-judge panel to immediately overturn the part of the voter-approved measure that lets the commission draw those lines. That would free the Republican-controlled Legislature to redraw the lines before the 2014 race — a move that likely would upset the current 5-4 edge that Democrats hold in the state’s congressional delegation.

Central to the question is a federal constitutional requirement saying the times, places and manner of holding elections for federal lawmakers “shall be prescribed in each state by the Legislature thereof.’’ That was the way the lines were drawn in Arizona through the 1990 redistricting.

The 2000 vote gave that power to the five-member commission. Proponents argued that would be less political than having lawmakers create districts designed to benefit themselves and their allies, to the disadvantage of political foes.

Republican legislative leaders sued last year to reclaim the power to at least draw the congressional lines, citing that constitutional language. They contend that provision allows the elected Legislature — and only the elected Legislature — to do that work.

But O’Grady said in the latest court filings the legislators are reading too much into that language. She reads it instead as an allocation of power between the states and the federal government.

“It’s talking about the legislative power of the state,’’ O’Grady said. “It’s up to the state to define how it’s going to exercise its legislative power.’’

In Arizona, O’Grady said, our state constitution gives that power both to the people and the Legislature.

“And the people established the commission to exercise legislative power over redistricting,’’ she said.

, something they are entitled to do.

Besides, O’Grady said, if the Legislature doesn’t like this system, “It is free to make and pass a new plan and submit it to the voters.”

House Speaker Andy Tobin, who is making a bid for Congress, and is one of the movers behind this lawsuit, had a plan to do that, but could not get it approved.

Further, O’Grady said the challenge by legislators comes too late — not just because the current process has been in place since the 2000 election, but because the Legislature was allowed to provide input into the maps crafted by the commission but chose to sue only after a majority of lawmakers did not like the final results.