Washington (CNN) -- Saying the United States is "falling behind" in education, Secretary of Education Arne Duncan worked Wednesday to persuade lawmakers that the Obama administration's plan to rewrite a federal education law is the right move for the nation's students and schools.
"A generation ago, we led the world, but we're falling behind. The global achievement gap is growing," he told the Senate Health, Education, Labor and Pensions Committee.
"If we're serious about preparing our nation's young people to compete in a global economy, we must, we must do better than this."
He cited statistics that 27 percent of American high schoolers drop out and that only 40 percent of the country's "young people" earn a two-year or four-year college degree.
"I believe that education is the one true path out of poverty. It has to be the great equalizer in our society," Duncan said.
On Saturday, the Obama administration released its wide-ranging plan for overhauling the No Child Left Behind education law. It shifts the focus from singling out underperforming schools to fostering a "race to the top" to reward successful reforms.
The proposed revisions promise that low-performing schools that fail to improve will be asked to show "dramatic change," but states and school districts will be held accountable for those shortcomings as well.
It supports the expansion of public charter schools and calls for giving states and school districts additional flexibility in how they spend federal dollars "as long as they are continuing to focus on what matters most -- improving outcomes for students."
And it allows them to use federal grant funds to change the way teachers and principals are paid "to provide differentiated compensations and career advancement opportunities to educators who are effective in increasing student academic achievement," among other considerations.
The newly published "blueprint" has come under fire from teachers' unions.
The National Education Association's president, Dennis Van Roekel, said the union was expecting "more funding stability to enable states to meet higher expectations."
He said, "Instead, the 'blueprint' requires states to compete for critical resources, setting up another winners-and-losers scenario. We were expecting school turnaround efforts to be research-based and fully collaborative. Instead, we see too much top-down scapegoating of teachers and not enough collaboration."
The president of the American Federation of Teachers, Randi Weingarten, said the plan puts all the responsibility on teachers but gives them no authority.
"For a law affecting millions of schoolchildren and their teachers, it just doesn't make sense to have teachers -- and teachers alone -- bear the responsibility for school and student success," she said in a statement. "Teachers are on the front lines, in the classroom and in the community, working day and night to help children learn. They should be empowered and supported -- not scapegoated."
The Obama administration's $50 billion proposed education budget adds $3 billion in funding to help schools meet these revised goals, with the possibility of an additional $1 billion if the overhaul plan passes Congress.
The 8-year-old No Child Left Behind law was one of the signature policies of the Bush administration. It set up a regimen of state reading and math tests for students in third through eighth grades, intended to identify failing schools. But critics have said that the Bush administration never properly funded the effort and that states needed more flexibility in meeting those goals.
Duncan said this week that the law was "too punitive."
He said, "It lowered the bar for students and too often narrowed the curriculum, and we have to flip all of that. We have to raise the bar: high standards for all students, meaningful college and career-ready standards."