In this April 30, 2014 photo, children in Erin Kling's, right, pre-kindergarten class recite the Pledge of Allegiance at the start of the school day at Stafford Elementary School in Tacoma, Wash. (Ted Warren/AP)

Chad Aldeman is an associate partner at Bellwether Education Partners, a nonprofit education consulting and research group.

After winning approval in the House and Senate, legislation ending the landmark No Child Left Behind Act was signed into law Thursday by President Obama. Although the new law enjoys broad bipartisan support, it’s important for anyone concerned about the quality of our schools to understand how radically it will diminish expectations for our nation’s public schools. By the time the law is fully implemented in 2018, most schools will be free from any sort of federal pressure to improve.

What has changed is the federal government’s answer to one fundamental question: Do all schools need to improve, or just the worst ones?

The No Child Left Behind Act (NCLB), signed into law in 2002, was by no means perfect, but it sent a clear message: All schools, and all students, had room to improve. The law held every school accountable for meeting objective standards for performance, and no matter how many schools failed to meet that standard, they all were told that they needed to take action. Over time, as expectations rose, so too did the number of schools failing to meet them. At the law’s peak, more than 19,000 schools — about two-fifths of schools receiving federal funds and one-fifth of all public schools nationally — were placed on lists of schools “in need of improvement” and subject to consequences built into the law.

In some ways, NCLB’s theory of action worked. Schools responded to the increased pressure with additional attention on low-performing students and more instructional time in math and reading. That’s exactly what was supposed to happen.

What the authors didn’t anticipate, however, was the political blowback from this pressure. If anything, the law worked too well, ratcheting up the number of schools identified for improvement and the consequences those schools faced.

As the law aged and those consequences rose, it became less and less politically acceptable to tell so many schools to improve, let alone expect states or districts to have the technical capacity to help them do it. When Obama took office, he began advocating for a different way to identify schools. Rather than the criteria-based system of NCLB — where standards were set in advance and any school could theoretically fail them — the president called for a system focused on a predefined group of schools that was smaller and, theoretically, more manageable.

Under his 2010 “blueprint” for reauthorizing the federal law, Obama proposed an accountability system that focused on the worst 5 percent of schools, along with an additional 10 percent of schools with large achievement gaps. Although Congress failed to take up that blueprint, Obama himself implemented this approach through large-scale waivers of NCLB that began in 2012. (I served as an adviser to the Education Department and worked on the waiver initiative from 2011 to 2012.)

The number of schools told that they needed to improve began dropping immediately, from a high of 19,270 after the 2011-12 school year to 16,548 in the first year of Obama’s waivers. As a few more states collected waivers and moved to their own relative ranking systems, the numbers dropped again to 15,536 in 2013-14.

Policymakers still think this number is too high. Under the new law, states will have to identify only the absolute bottom 5 percent of schools, and since that rule applies only to a subset of public schools that accept federal funds, we’ll be down to identifying just 2,750 schools. From NCLB’s peak, states will let about 17,000 schools off the hook for meaningful improvement.

To be clear, there is no “right” number here. And there’s an inherent tension between how many schools are identified for improvement and how much can be done to help them improve. But the problems in our education system are not isolated to just the worst of the worst schools. Low-performing and mediocre schools are spread across all kinds of communities.

Ironically, while Democrats are often considered to favor strong federal rules and Republicans local control, those roles are reversed here. It will be the Republican George W. Bush administration that put in place the large increase in federally mandated school accountability, and the Democratic Obama administration that ends it.

Perhaps worst of all, a strategy focused on fixing the toughest problems hinges on the desire and ability to actually do something about poor performance. The Obama administration, to its credit, did allocate significant resources to chronically low-performing schools through its School Improvement Grants program. And in exchange, it required tough and aggressive interventions in those schools. Although the results of those efforts are still uncertain, they represent a real attempt to shake up persistently poor-performing schools.

The new law will do nothing of the sort. The tough interventions envisioned under the original Obama proposal were attacked as too draconian and inflexible, so the new law will let each district with a low-performing school — remember, these are the low-functioning districts that let the school flounder in the first place — decide what’s best for them. There are no consequences for inaction, and local leaders who do want to make aggressive interventions will get no political cover from Washington. After shaming the worst of the worst schools, we’ll pretty much leave them on their own.

This new theory of action relies on, well, not much action at all. Few schools will be told they need to improve, and those few won’t receive the support they need. It appears our political system simply couldn’t tolerate anything stronger.