"When I am governor, there will be universal pre-k for all children," said Massachusetts Attorney General Martha Coakley, who lost her Democratic bid for governor this year, on the night of the primary election. Tom Wolf, a Democrat who will soon take office as Pennsylvania’s next governor, touted the need for universal pre-k throughout his campaign and listed it as a goal on his election website. As did Maryland’s Democratic gubernatorial candidate Anthony Brown, who lost.

And it wasn’t just the Democrats. Rick Snyder and Greg Abbot, both of whom won their Republican bids for governor, highlighted their support for pre-k in Michigan and Texas, respectively. (Their Democratic opponents did, too.)

In edu-speak, pre-k typically refers to a specific category of early learning that focuses on ensuring kids are prepared for kindergarten. The premise is that a child’s readiness for kindergarten can put that student significantly ahead of one who isn’t ready. This is what causes the achievement gap, and that gap only widens over time.

Pre-k programs are often funded by the government and, at least theoretically, entail high standards: qualified teachers with bachelor’s degrees, small class sizes, low teacher-student ratios, family support services, and nutrition requirements, among others. Many of them are operated in conjunction with public school districts. The federal Head Start program, which contracts with private agencies to provide early education and social services for low-income families, has similar qualities to pre-k, though it serves a broader age group (from newborns to 5-year-olds) as well as expecting mothers.*

A number of states offer universal pre-k, pre-k for all 4-year-olds, while most target it at specific populations. (Nine states lack any form of state-funded pre-k.) A few states have as many as three-fourths of their 4-year-olds participating in government-funded pre-k, including Oklahoma, Florida, and Vermont. But nationally, just a small fraction of 4-year-olds participate in those kinds of programs: 28 percent, according to 2012-13 data from the National Institute for Early Education Research, or NIEER.

The push for pre-k traces back decades, though the movement has undergone a revival in recent years. In his state of the union speech last year, President Barack Obama pledged to develop a federal $75 billion universal pre-k program that would involve partnering with the states, though the initiative has made little progress. Meanwhile, governors and state policymakers across the country have campaigned for expanding access to early education.

And other sectors have joined the cause, too, including business leaders and big-box corporations that say pre-k is key to developing a skilled workforce and stimulating the country’s economy. Moreover, pre-k is seen as an economic investment because it’s believed to reduce the chances a kid will drop out of school, get arrested, and rely on social services, as well as significantly increase that person’s earning potential.