Hesitating to fully embrace a nationwide campaign to bolster schools' accountability, California has turned up its nose at federal carrots and now wants a reprieve from Uncle Sam's stick -- an entreaty that has so infuriated the Obama administration that it is threatening to withhold federal money from the state's schools.

Despite ostensibly working toward the same goal to improve public education, especially for disadvantaged children, Sacramento has resisted the changes in school accountability and teacher evaluation sought by Washington.

On Tuesday, the state Senate overwhelmingly endorsed a bill that creates a new state testing regimen -- one supporters heralded as promoting more meaningful learning, and less drill and memorization. Known as MAPP, the exams will be field-tested by some schools in the spring.

But the bill -- expected to pass the Assembly and be signed into law -- will let California ditch its STAR tests, the mainstay of its school accountability system. For more than a decade, public schools each spring have administered the standardized tests, which generate scores widely used to judge the success of schools and districts.

Now that index may not be published for up to two years. And that puts the state in conflict with a federal requirement to test students and broadcast the results -- a requirement State Superintendent of Public Instruction Tom Torlakson would like to have waived for California.

But this week, U.S. Education Secretary Arne Duncan issued a peremptory response: "A request from California to not measure the achievement of millions of students this year is not something we could approve in good conscience," it read. "Backing away entirely from accountability and transparency is not good for students, parents, schools and districts."

The reaction took state officials, who have been talking with Washington, aback. "I was a bit surprised at the timing," said state deputy superintendent Deb Sigman.

State officials argued that it's unfair and meaningless to use old tests to assess how students do on new material, or to publish results of the still-unrefined MAPP, or Measurement of Academic Performance and Progress.

If the dispute isn't resolved, it's not clear if or how much Uncle Sam could refuse to pay to California schools. While local and state taxpayers foot most of the K-12 bill, federal funds pay for key programs. For instance, of San Jose Unified's $286.8 million general fund, 5.3 percent comes from the federal government.

More than any of his predecessors, Duncan has pressed vigorously for states to hold schools accountable for student achievement and teacher improvement.

But California has resisted, despite the No Child Left Behind law, which requires states to bring growing numbers of students to proficiency or suffer sometimes-drastic consequences like school closures and takeovers. While most states recently have sought and won a way out of those federal threats, California was among just a handful that refused to seek a waiver of the law.

That's because to win the waiver, states had to promise to base teacher evaluations at least in part on student test scores. California, swayed by powerful teachers unions, has resisted incorporating standardized test scores into teacher evaluations.

In general, as they begin teaching the new Common Core curriculum adopted by most of the 50 states, school officials welcome the reprieve from publishing test scores.

"We need this year and all of next year prior to the spring of 2015 to fully prepare for these changes," said John Porter, superintendent of the Franklin-McKinley School District in San Jose.

In the spring, schools may voluntarily take either the English or math portion of the new MAPP exams. The state will pay for one, but not both, of the online-only tests.

A district wanting to administer both English and math will have to pay for the extra test.

Some districts, like East Side Union High in San Jose, would prefer to take both portions. "You would think that Mr. Duncan would want a large sample piloted to be sure that the tests are reliable," Superintendent Chris Funk said.

California could end up with one of the largest pilot tests in the nation. Many states plan to test only 10 percent of students while using their current standardized exam for the test of their students.

Many districts are still incorporating Common Core into the classroom. For example, Cupertino Union for a year and half has sent teams from each of its 26 schools to curriculum training, and to return to help train their colleagues.

"We are giving the gift of time to teachers and students," said AB484's author, Susan Bonilla, D-Concord, a former English teacher, referring to the hiatus from releasing scores. "We want you to focus on classroom instruction. I understand the pressure a teacher feels when she knows an assessment is coming."

Contact Sharon Noguchi at 408-271-3775. Follow her at Twitter.com/noguchionk12.