WASHINGTON — With Congress poised to vote on a long-overdue bill to replace No Child Left Behind, the country’s main K-12 education law, opponents on the far right and left are trying to scuttle the bipartisan measure.

Heritage Action for America, the political arm of the conservative Heritage Foundation, urged lawmakers Tuesday to vote against the measure, calling it “a step backwards for conservative education policy” because it maintains too much federal control over local schools and extends it with the creation of a new preschool initiative.

The group said it will include the vote in its legislative score card.

Meanwhile, a coalition of 100 civil rights groups, including the Southern Poverty Law Center and the NAACP Legal Defense and Educational Fund, also voiced opposition, saying the legislation goes too far to weaken federal oversight of the country’s 100,000 public schools. The coalition said it was particularly concerned that the bill does not address disparities in the ways public schools discipline disabled and minority students.

At the Capitol, House Speaker Paul Ryan confirmed plans to bring the compromise education bill for a final vote this week. A vote in the Senate is expected to follow next week.

“We expect to have very good majority support,” Ryan said. “These are great conservative education reforms. I think it was quoted in the paper yesterday that this is the greatest devolution of power back to the states in education in 25 years”

A raft of national groups, from the National Governors Association to School Superintendents Association to the two major teachers unions, have lined up in support of the bill.

No Child Left Behind was due for a rewrite eight years ago, but Congress has struggled to find agreement on the proper role of the federal government in local schools.