Gubernatorial candidate Jared Polis wants to make preschool and full-day kindergarten free. That could prove tough.

Democratic U.S. Rep. Jared Polis of Boulder, the latest Democrat to enter the 2018 governor’s race, faces an uphill battle in fulfilling one of his first campaign promises: providing free preschool and full-day kindergarten to all Colorado kids.

After a visit Monday to a charter school he helped start, Polis told Chalkbeat he would create a bipartisan group to craft ballot language asking voters to increase taxes to cover the hundreds of millions of dollars required.

“We’re going to build a winning coalition,” he said. “We’re going to have Republicans and Democrats. We’re going to have the business community. We’re going to have educators. And we’re going to speak right to families about how important full-day kindergarten and preschool is and what a positive difference it can make in their lives.”

However, Colorado voters historically have rejected statewide tax increases for education, and state lawmakers have little appetite to spend existing money on early childhood education.

Backers say preschool and full-day kindergarten can help students, especially low-income students, develop early reading and math skills — along with social and emotional skills that help kids keep emotions in check, solve conflicts and build healthy relationships.

It’s unclear how much it would cost to pay for universal preschool access. The state spent $86 million in 2015 to send more than 21,000 at-risk 3- and 4-year-olds to preschool through the Colorado Preschool Project.

To pay for full-day kindergarten for all Colorado students, the state would need to spend about an additional $250 million, according to a 2016 legislative analysis.

Colorado school districts receive a little more than half the average per pupil amount for kindergarten students compared to students in higher grades. School districts must make up the difference if they offer full-day kindergarten. Some districts have asked voters to pay for the program, while others charge tuition.

State Rep. Jim Wilson, a Salida Republican, has attempted to send more money to the state’s kindergarten classrooms for the last three years. He said he welcomed Polis’s commitment, but was skeptical.

“There’s a whole lot of difference between an election and reality,” he said. “I don’t see the governor’s office, no matter who is in there, sending a budget with $250 million for full-day kindergarten.”

Some of the state’s most conservative lawmakers oppose expanding funding for early childhood education because they believe parents — not the state — should be responsible for early learning.

Polis said it would not be mandatory for families to enroll their children in preschool.

“What we’re talking about is making preschool available to families,” he said.

Polis has a lengthy resume on education issues. He’s helped launch charter schools, is the former chairman of the State Board of Education and most recently became the highest ranking Democrat on the U.S. House’s Early Childhood, Elementary, and Secondary Education Subcommittee.

Other Democratic candidates who have announced for the 2018 race include U.S. Rep. Ed Perlmutter, former state Sen. Michael Johnston, former state treasurer Cary Kennedy and businessman Noel Ginsberg.

Current Republican candidates include George Brauchler, the 18th Judicial District attorney; Victor Mitchell, a former state lawmaker; and Doug Robinson, a businessman and nephew of former presidential candidate Mitt Romney.

Chalkbeat Community Editor Ann Schimke contributed.