Public schools would be better if two major obstacles were removed. Teachers’ unions have injected too much partisanship into schooling, and conservatives have undercut the promise of a good education for all students.

These two issues are interconnected. The more the teachers’ unions became involved with endorsing candidates for public office, the more the conservative politicians, who were often not union-endorsed, hardened their opposition to public education. Conversely, the more the conservatives attacked public education, the more the unions used partisan politics to blunt it.

This harmful pattern must stop. Partisanship should be removed from public education, and the ideal must be that all students are entitled to a good education.

History helps to explain how the teachers’ unions and the conservatives became locked in fighting one another, thereby distracting attention from improving education.

The National Education Association (NEA), the bigger union, represents about 70% of all teachers and mostly serves teachers from outside large cities. The American Federation of Teachers (AFT), the other union, represents the remaining teachers and is found mostly in large cities.

The AFT, which is 100 years old this year, has always called itself a union. The NEA, which was founded in 1857, calls itself a professional employee organization and throughout its history has provided a variety of services for teachers. In the 1960’s, the NEA began taking on more of the functions associated with trade unions, most notably collective bargaining in states that permit it, and sought a more forceful role in improving the pay and working conditions of teachers.

Both unions endorse candidates for public office, give them contributions for their campaigns, and provide field workers in their efforts to get elected. Both unions have consistently endorsed Democratic candidates for the presidency and overwhelmingly support Democrats for Congress, as governors, and as state legislators. This support has given the unions a strong voice within the Democratic Party. Naturally, Republicans are not pleased with that partisan kinship.

The political alignments around public education were not always the way they are now. The Republican Party, founded in the mid-1850’s, was a strong supporter of public education for the first century of its existence and beyond. For example, Republicans successfully urged states to adopt an amendment that barred public aid to private schools.

During that same period, the Democratic Party had many members who favored aid to private schools. Until the 1970’s, white southerners who wanted to maintain legal segregation of the races and the option of private schools for their own children, and northern Catholics who sought support for parochial schools comprised large blocks of Democratic votes.

The parties switched their positions in the 1970’s. President Richard Nixon adopted a “southern strategy” to bring white southerners and northern Catholics into the Republican Party through advocating for vouchers for private school tuition. Those two groups were restless because of growing Democratic support for civil rights.

President Ronald Reagan continued that strategy, very successfully in the southern states and significantly successful in the north. It took a few years for the Republicans to shift from their century-old positions of support for public education and for civil rights, but by the 1980’s the process was largely completed.

The Democrats moved in the opposite direction and increasingly opposed vouchers and solidified their support behind public education. The new and growing influence of the teachers’ unions in the party at that time played a strong role in the shift.

As the parties flipped their positions on public education, their policies hardened. Conservatives pushed programs meant to weaken the teachers’ unions, such as advocating for charter schools, which employ a far smaller share of unionized teachers than do traditional public schools. In state legislatures and the Congress, the teachers’ unions fought those attempts tooth and nail as threats to public education.

The evidence shows that, overall, the conservatives’ emphasis on tuition vouchers, tuition tax credits, and charter schools has not produced large or widespread improvement in American education. While examples exist of effective charter schools and other successes, this is not a common pattern. In addition to this lack of major success in raising student achievement, these approaches help only a small percentage of students and thereby do not further the goal of a good education for all students.

The union strategy of using politics to improve schools has often inadvertently helped the other side, which feels aggrieved by the unions’ pattern of endorsing Democrats for public office. When Republicans have taken control of Congress and state legislatures, they have often tried to push through legislation that weakens unions and provides funds for private schools.

It’s time to end this combat between unions and conservatives, each feeling aggrieved by the other and trampling on children’s schooling in the process.

The teachers’ response to this plea will be that the unions cannot find many Republicans to support because of their anti-union and anti-public school policies. On the other side, the Republicans will assert that their remedies while now directed at a few students will ultimately help all students. Although each response has some validity, more importantly those answers show how divided American society has become.

This continuing battle is not good for public education. It is draining resources, time, and energy from basic issues, such as how can all students in public schools have good teachers who are well-supported in their work?

Recently, some hopeful signs have appeared. The NEA and congressional Republicans collaborated on last year’s education bill, and are still working together. The issues they commonly support are quite controversial with criticism of the NEA coming from some other education and civil rights groups, but the organization’s spirit is the right one—to attempt to reach across the ideological divide.

In the last 50 years the political parties have swapped their positions on public education, and in the process the political divide has deepened. These events have to do with politics and not education.

Recognizing this, can’t we put politics aside and seek common ground on ways to improve public education? Since over 90% of America’s students attend public schools, our children’s future depends on those schools being good schools.

This article first appeared as a blog by Jack Jennings on the Huffington Post of May 18, 2016.