A coalition of more than 25 organizations representing more than 5.5 million active and former members of the U.S. military just told Congress it opposes legislation backed by Education Secretary Betsy DeVos that would allow military families to use public money for private-school vouchers.

The Military Coalition sent a letter (see text below) to House leaders saying that H.R. 5199, called the Education Savings Accounts for Military Families Act, would divert critical revenue that goes to school districts. The missive said it would be “financially devastating for many school districts, critically compromising the quality of the education they could provide to military children and their civilian classmates.”

DeVos has been advocating for military school vouchers, including during a visit in April 2017 to Fort Bragg in North Carolina. She has long been a proponent of alternatives to traditional public schools and has said her chief priority as education secretary is to expand them. Critics say that public money should not be used for private and religious school tuition, as DeVos advocates, and that she is seeking to privatize public education. She denies it.

There are nearly 600,000 school-age military children, and more than 80 percent attend public schools in their local communities. More than 72,000 students attend 166 public Defense Department schools in 11 foreign countries, seven U.S. states, Guam and Puerto Rico, according to the Department of Defense Education Activity, an agency that runs pre-K through 12th-grade educational programs for stationed military families.

The legislation at issue would divert what is known as Impact Aid, which is a revenue source for many schools serving military families. The aid helps districts offset property tax revenue that is lost because of nontaxable federal land, such as a military base. Impact Aid is already funded at less than 60 percent of what it should be to cover district needs as set in the law.

DeVos has faced resistance to her push for vouchers for military families, including during her Fort Bragg visit and now by the Military Coalition. The coalition includes groups such as the Air Force Association, the Association of the United States Army, the Association of the United States Navy, the Military Officers Association of America and the National Military Family Association. Together, they represent more than 5.5 million current and former officers and their families and survivors.

In a letter to House leaders, the coalition said:

Additionally, we note that relatively few military families would be eligible for an ESA [Education Savings Accounts] under the legislation — and among those that would be eligible, the majority would receive ESA’s of only $2,500. No children of service members in the National Guard or Reserves would be eligible. It is counterproductive to defund Impact Aid, a successful program that has long enjoyed bipartisan support, in order to provide a benefit of questionable value to a minority of military students.

The letter was sent to Rep. Virginia Foxx (R-N.C.), chair of the House Education Committee; Rep. Robert C. “Bobby” Scott of Virginia, the leading Democrat on the House Education Committee; Rep. Mac Thornberry (R-Tex.), chairman of the House Armed Services Committee; and Rep. Adam Smith of Washington state, the leading Democrat on the House Armed Services Committee.

Here’s the letter:

( Correction: An earlier version identified Rep. Virginia Foxx as being from Virginia. She is from North Carolina.)