“I can go to jail!” said one mother enthusiastically, as a crowd of protesters gathered near Capitol Hill. “But you’ll need to pick up my kids this afternoon, so don’t get yourself arrested,” she admonished another mother standing nearby.

That exchange, recounted in Virginia Walden Ford’s book “Voices, Choices, and Second Chances,” came in the early days of the fight for school choice in D.C. Impassioned parents had decided they could no longer let their children drown in the tide of mediocrity endemic in the government education system.

Throughout the 1990s and into the early 2000s, they rallied, protested, and engaged with members of Congress. There were setbacks, such as President Clinton’s veto of a 1998 bill that would have created a scholarship option for District students. But the parents persisted.

And in 2004, they won a major victory. That’s when the D.C. Opportunity Scholarship Program was signed into law, creating scholarships for children from low-income families living in the District to attend any private school of their choice. Those scholarships have been life-changing for children in the nation’s capital.

An evaluation of the program, published by the Department of Education, found that participating students graduated at a rate 21 percentage points higher than their peers who applied for, but did not receive, a scholarship. That is, 91 percent of the kids able to use the voucher program successfully graduated, compared to only 70 percent in the control group.

Participants have not yet demonstrated significant improvements in test scores outcomes for participants, but there are indications that the program has the potential to have even more meaningful, long-term effects on students’ future academic attainment and other positive life outcomes. Moreover, parents and students are significantly more likely to feel that they have access to safe schools as a result of the program.

The bottom line: the D.C. Opportunity Scholarship Program significantly improves graduation rates and school safety — and does so for a fraction of the money spent on students in D.C. Public Schools.

Ms. Ford’s book describes the parents’ emotions in the years between Mr. Clinton’s 1998 veto and the program’s enactment in 2004. “We were on a roller-coaster ride of tremendous support, surprising betrayals, and hard-won victories,” she writes.

Incredibly, in 2018, little has changed.

Despite the program’s success in empowering poor parents to find safe and effective schools that are the right fit for their children, its future is uncertain. Funding remains a political football. And student eligibility rules undercut the program’s ability to serve more students.

The Opportunity Scholarship Program relies wholly on annual appropriations from Congress. And that has, inevitably, become highly politicized.

The Obama administration, for example, attempted with nearly every budget cycle to zero-out program funding. And in a breathtaking show of disregard for the educational choices made by families participating in the program, then-Education Secretary Arne Duncan went as far as to rescind hundreds of scholarships that had already been awarded to students.

In order to expand and strengthen the D.C. Opportunity Scholarship Program, scholarships should be funded through a process similar to District public and charter schools’ formula and based on student needs (such as higher amounts for children with special needs). Furthermore, lawmakers should remove the income eligibility caps, which limit how many children can participate annually.

These updates would enable the program to serve more students for generations to come. After a generation of fighting for school choice, the District’s parents and students have earned that.