The eight-year effort to reauthorize No Child Left Behind (NCLB), the controversial bill that sets federal education policy, has come down to a battle over testing and accountability among some odd bedfellows.

All sides agree that an updated law is an urgent necessity. But the question of what role standardized tests should play and how to hold underperforming schools to account divides deeply.

To teachers’ unions, the NCLB’s aggressive testing regimes, combined with ambitious targets for annual progress, have straitjacketed education. Actual classroom learning has suffered as teachers narrow the curriculum to simply “teach to the test,” they say. Curiously, they’re joined by tea partyers who see the law’s mandates as federal meddling.

But for civil rights groups, NCLB – for all its shortcomings – was responsible for finally shining a spotlight on the groups with the biggest educational needs. Through its tests, NCLB directed attention to how to close the persistent achievement gaps between white students and many minorities. Abandoning NCLB’s principles, they fear, could mean a return to a time where poor and minority students slip through the cracks and schools aren’t held accountable for providing them with a good education or raising achievement levels.

Congress’s task has been to try to find a bridge between these two positions. This year, the prospects for finding common ground are perhaps brighter than they have ever been, some experts say. Neither side’s concerns have dissipated, but there is a mounting consensus that to save the good that NCLB has done, a greater degree of flexibility might be needed.

“The federal role needs to be scaled back in some ways,” says Anne Hyslop, a senior policy analyst with Bellwether Education Partners. “Republicans want to dial the scale back from a level 10 to a level 0 or 1, while Democrats would want the scale to end up more in the middle.”

Draft bills to reauthorize the Elementary and Secondary Education Act, the official name of the act that got rebranded as No Child Left Behind in 2001, are before both the House and Senate. With Republicans in control of both chambers, the bills are moving forward rapidly.

Republicans have a “fairly strong negotiating position,” says Martin West, an education professor at Harvard University in Cambridge, Mass. “At the same time, they want a bill that ultimately the president will sign.”

The Obama administration has sided with civil rights groups to demand that any rewrite not abandon the testing and accountability mandates they see as crucial to ensuring that less-advantaged students aren’t forgotten.

Ahead of a key House committee vote Wednesday, a coalition of 34 civil rights groups – including the NAACP, the National Urban League, and the National Council of La Raza – argued that the current Republican drafts in the House and Senate strip away important provisions.

“We’re not willing to accept any reauthorization that rolls back protections and resources that have made a world of difference in the lives of our nation’s most vulnerable children,” said Wade Henderson, president and CEO of the Leadership Conference on Civil and Human Rights, in a conference call with reporters.

Civil rights groups acknowledge problems with NCLB – in particular the one-size-fits-all consequences it imposed on schools and districts where targeted achievement goals weren’t met. But other issues, such as the sheer number of tests in some states, have more to do with additional state and local tests that have been piled on, they say.

Under NCLB, 17 tests are mandated: annual math and reading tests between grades 3 through 8 and once more in high school, plus a science test in elementary, middle and high school. But other state and local tests have proliferated and added to the burden.

Finding a balance between state and federal efforts to enforce accountability is likely to be where compromise happens. Some Republicans chafe at the top-down approach that allows the federal government to dictate education policy to the states.

Even supporters of NCLB acknowledge that there needs to be more flexibility. Giving districts and states more latitude in choosing which evidence-based responses to use with failing schools could help, said Chanelle Hardy, executive director of the National Urban League, in the press call.

But she wants to ensure that the pendulum doesn’t swing too far in the other direction.

“The way we react to the information we receive is where the rubber meets the road,” she said. “We don’t want to lose sight of the critical information about whether and how students are making progress.”

Indeed, despite all the discussion of testing, annual requirements are likely to remain. The vocal anti-testing faction flooded congressional inboxes with e-mails over the weekend, but polling data show a fair amount of support for federal testing requirements, notes Professor West of Harvard.

But states can and should have more control over how they use those test results and how they address schools that don’t measure up, he adds.

Not everyone agrees with West, or the civil rights groups, that the continuation of annual testing is what's best for low-income and minority groups.

Those vulnerable groups have, in some ways, been harmed by the laser focus on testing, argues Monty Neill, executive director of Fair Test, a Boston-based group that questions the reliance on standardized tests. Since NCLB ushered in the era of testing in 2001, the rates of improvement for most high-needs groups have actually stagnated, he says.

“We think a significant possible explanation is that people went so test bonkers on their own state testing that they narrowed instruction to what would boost student scores,” adds Mr. Neill.

He says there is a role for accountability, and even for standardized tests, in a limited form. But even if a new version of NCLB pays lip service to using other measures in evaluating schools, he worries that the “inertial effect” will make most states continue on the same testing-centric path they’re on. He’d prefer to see a more holistic approach to how schools are evaluated.