The most important thing in the news last week — apart from the coming of Pope Francis and the going of Yogi Berra — was the rising discussion in Nashville about the educational needs of children.

The shorthand educators use for this is “pre-K” — meaning instruction before kindergarten — and the big idea is to prepare 4-year-olds and even younger kids to be ready to succeed on their K-12 journey.

But it gets complicated. The concept has multiple forms, and scholars and policymakers grapple with the shape, scope and cost of the ideal program.

The history of early education is long, especially in Nashville. For over half a century Vanderbilt’s Peabody College has been a big part of the nation’s pre-K learning curve. (Disclaimer: Vanderbilt is a client in my day job, and I have worked with Peabody research faculty. But maybe the larger influence on me was my mother, a Peabody grad and elementary teacher.)

The federal Head Start program, launched 50 years ago, has served more than 30 million children. It was based on concepts developed at Peabody by Susan Gray, the legendary pioneer in early childhood education research, studying the effects of poverty on children’s intellectual and social development.

A new Peabody study of the Tennessee Voluntary Pre-K program reports that pre-K works, but the gains are not sustained through the third grade. Seems to me this highlights quality issues in elementary schools more so than pre-K — and how a longer-term success must connect pre-K with all the other moving parts of educating a child.

Pre-K is controversial. Some critics say it is a frill and shouldn’t be free to families able to pay. Pre-K advocates insist it is proven and will succeed if integrated with the rest of the child’s schooling, requiring better organization and funding. I lean toward the latter view.

This is, in any case, the right conversation to be having now as Mayor Megan Barry takes office. She was the first candidate to speak out for strong pre-K programming. The important thing is for all of us to keep in mind the real goal and the longer, bigger picture.

The weight of the evidence is on the side of pre-K, that early intervention works. What government has not yet found is the political will to put that understanding into full practice with a sequence of smart schooling that provides the early foundation, then systematically builds on it.

For this high purpose, our schools need both the talent and the organization to educate each child who arrives at the schoolhouse door. Some show up ready, but many do not at this critical time when young brains are developing rapidly.

It should not matter what ZIP code you live in, but in Nashville too many children — through no fault of their own — come from homes in poverty. While some kids arrive bright, eager and ready, others show up damaged, hungry and emotionally malnourished, already deprived of many life experiences compared with their young peers.

Excellent teachers respond to them all. But children who arrive better prepared also can fall behind as busy teachers work to lift up the disadvantaged kids. When this continues through all grades, it is why some parents with choices opt out, leaving others behind to flail.

The point of education is to make all our children discerning citizens who understand their world and why good choices matter. This is important because we will need many of them to become our mayors and governors and senators, our counselors and priests and presidents, as well as good parents and teachers themselves.

The full pre-K toolkit — with a continuum of learning, enrichment and good expectations — will have a sure cost, but without it the ablest educators will forever struggle uphill. And the rest of us will ever wonder why failing kids (and schools) never catch up.

Our best teachers and brightest researchers know this. Policymakers should listen to them now and sustain the commitment to early learning.

Keel Hunt is a Tennessean opinion columnist. Reach him at Keel@TSGNashville.com.