For the first two hours or so, yesterday’s Senate hearing on the state of preschool and other early-childhood services in New Jersey went pretty much as expected.

Virtually nobody was against expanding the state’s preschool program, and plenty of research was provided as to benefits of existing programs.

But the arguments crystallized — and the attendees figuratively caught their breath – when a veteran kindergarten teacher from Freehold came forward with a packet of Week One assessments from some of her new students.

Randee Mandelbaum’s new students were asked to draw crayon self-portraits and demonstrate how well they knew their letters and numbers. On the left side of the sheets was the work of children who hadn’t been through preschool, and on the right side were those who had.

And one by one, the former showed random drawings and illegible scribblings, compared with clearly recognizable self-portraits — including fingers and shoes — as well as one child who could count to 20 and another who wrote out the alphabet, capital and lower case.

“You will see one student does not know any letters, cannot write any letters, and doesn’t even know how to write her own name,” said Mandelbaum, a 20-year veteran. “While the other student can write most of the alphabet comfortably.”

Those were just the obvious differences, she said. The kids who had been to preschool were better to separate from parents, go to the bathroom on their own, follow two- or three-step directions, use scissors, and interact with peers. And the gaps remain through the year.

“The children with pre-K knowledge and experience nearly always come into my class with the essential social, emotional, and academic skills, able to launch an essential year in kindergarten,” Mandelbaum said.

State Sen. Teresa Ruiz (D-Essex), the chair of the Senate committee, flipped through the student work in wonder.

“Of all the testimony we have received today,” she said. “If anybody needs the proof, in New Jersey we have the evidence, and it is our responsibility to step up our game and find the investment. This is extraordinary.”

Ruiz had called for the hearing, saying she wanted to jumpstart the discussion on bringing universal preschool to the state, expanding on the successful court-ordered program now serving the state’s most impoverished districts with two years of full-day programs.

Also on the table, Ruiz said, were other early-childhood services, including those that come before pre-K, and building out full-day kindergarten so that it is in every district. State officials said about 85 percent of districts have full-day, the rest half-day.

The line-up of guests included many of the state’s top advocates on the issue, including state Early Childhood Director Ellen Wolock, all the main education organizations, leaders of individual child centers and United Way programs, and the top researcher from Rutgers’ National Institute for Early Education Research.

“I am pleased to be in a state that has made substantial progress in providing high-quality preschool,” said Steve Barnett, NIEER’s executive director. “New Jersey already has a proven approach.”

Barnett argued that high-quality preschool across the state would save $850 million a year in K-12 costs in terms of remediation and special education.

Yet the stumbling block will be finding the down-payment from the state to move the program forward, one that already costs $600 million and serves 40,000 students.

Ruiz said afterward that all options were being considered, including better coordination among agencies and freeing up or leveraging existing funds. But she acknowledged new revenues would also need to be found.

“Should we put up a bill to explore a corporate business tax?” she said. “Maybe that’s the simplest thing we can do. Allocating money in next year’s budget, if that’s available. And exploring the option of a referendum, if that’s possible.”

Asked for specifics, she said the discussions were just beginning: “We don’t know yet. It’s too early.”