Jan 2 2016, 2:25 pm ET  ""  Early in his tenure as U.S. education secretary, Arne Duncan was one of the most popular members of the president's cabinet, praised by Republicans like Jeb Bush, invited to play in the celebrity basketball game during the NBA's All-Star weekend and embraced by education experts on the left and right.
But Duncan, who officially stepped down this week, leaves Washington as a deeply divisive figure. Over the last seven years, the Chicago native has aggressively implemented his vision for American education, in a more comprehensive way than perhaps any cabinet officer in the Obama administration has changed policy in his issue area. The rise of the Common Core education standards, a huge growth in the use of data in education and a strong push for accountability on colleges are among Duncan's signature projects.

Image: Arne Duncan

Arne Duncan, left, speaks with a senior student Stephanie Gil, right, after roundtable discussion with local students, parents and educators at the Benito Juarez Community Academy in Chicago, Monday, Dec. 16, 2013. Kamil Krzaczynski / AP
Valerie Strauss, an education columnist at the Washington Post and strong critic of Duncan, recently called him "the most powerful federal education chief in the department's history."

"He definitely expanded the role of the Department of Education," said Tom Loveless, an education policy expert at the non-partisan Brookings Institution.

By wielding that power, Duncan has become the rare figure in an era of deep partisan polarization to be hated by many on the left and right simultaneously. The National Education Association, the nation's largest teachers union and a powerful force in Democratic politics, called for Duncan's resignation last year, arguing he was too supportive of standardized testing.

Earlier this month, Congress passed the "Every Student Succeeds Act," a replacement to the Bush-era "No Child Left Behind" law. Included in the ESSA, at the behest of congressional Republicans, are several provisions that explicitly bar the federal Department of Education from setting policy for all of America's schools. Republicans wanted to ensure there are no more Arne Duncans.

Mission accomplished?

Duncan is one of only two members of Obama's cabinet (Agriculture Secretary Tom Vilsack is the other) to have served in his post since the start of the administration. And he will leave office having accomplished many of his goals.

Duncan helped convince 42 states to adopt education goals based on the Common Core, and 21 of them to use tests that directly align with those standards, which were created by a bi-partisan group and attempt to both make U.S. schools more challenging and the curriculum more similar from state-to-state.

While some liberals dislike charter schools, Duncan has been a strong supporter of them and presided over a huge growth in students attending charters in cities like Washington, D.C. and New Orleans.
He pushed through, over the objections of some university administrators, a comprehensive "College Scorecard" that creates a database that makes it much easier to figure out which schools don't do well in terms of making sure their students graduate and get jobs after college. Duncan quietly but dramatically changed America's college loan program, putting millions of students into a federally-funded program that caps loan payments at 10 percent of a person's income and forgives most loans after 20 years.

Duncan and his department have successfully urged school districts across the country to stop suspending students in kindergarten or elementary school, arguing such punishments are excessive and tend to disproportionately hit black and Hispanic students. He and his department also forced some colleges to overhaul their systems for preventing and investigating rapes on college campuses.
A move by both Duncan and Obama to highlight the importance of community colleges has created a growing movement, even in some Republican areas, to make tuition at those schools free. Amid the rise of for-profit colleges like the University of Phoenix, Duncan has been one of their strongest critics and used the power of his office to impose new restrictions on them.

"I came here very hopeful, also sometimes not sure what the federal government could do and be productive," Duncan told NBC News in an interview last month as he prepared to leave office. "It so exceeded my wildest hopes."

It's too soon to tell if these changes have made lasting impacts on improving college graduation rates, reducing the gap in performance between minority and white students, or getting test scores for the U.S. students closer to those of high-performing countries abroad, some of Duncan's primary goals