As President Obama encouraged the nation's schoolchildren to get serious about their studies, six longtime education activists marched in front of the Department of Education Tuesday in protest of the administration's spending cuts to a voucher program that pays for low-income children to attend private school in Washington D.C.

Obama has assured Americans he's doing everything he can to make sure they get the education they need. But critics right in his backyard believe he can do more, particularly for the 216 low-income D.C. students barred from private and parochial schools because Education Secretary Arne Duncan extended vouchers only for the 1,700 students already in the program.

"It's deplorable the way these children in this program have been treated -- kids' scholarships were revoked," said Virginia Walden Ford of DC Parents for School Choice. "They were -- they thought they won private school this year, schools that their parents chose, schools that would work for them."

The D.C. Opportunity Scholarship Program was slated to end next year because of a provision slipped into Congress' $410 billion omnibus spending bill by Sen. Richard Durbin, D-Ill., whose children attend private school. But the program was funded with $12 million in the upcoming school year to keep the vouchers running until the 1,700 children currently in the pilot program complete their studies. The program would not be extended beyond that, according to the White House.

"It was like a slap in the face," one parent said. "I worked so hard to find the right school for my daughter with the help of the DC Opportunity Scholarship Program. Then to have President Obama's secretary of education take that away? I feel betrayed."

Duncan told FOX News the students still in the voucher program are there because of him.

"There's students currently in schools and I advocated for them to stay there, where students were safe and learning and doing well," Duncan said. "We didn't want to pull them out of those schools. At the end of the day, we can't be satisfied with saving 1 or 2 percent of children and letting 98 or 99 percent down."

Since Washington began an aggressive effort to reform its schools two years ago, the percentage of elementary school students passing a math proficiency test has risen from less than a third to nearly half.

FOX News' James Rosen contributed to this report.