Federal early-childhood education programs aren’t doing nearly enough to meet a tidal wave of demand at the state level, in the view of U.S. Sen. Tom Harkin, D-Iowa, the sponsor of a multibillion-dollar dollar bill that seeks to dramatically expand the federal role in early-childhood education.

But his legislation, which is based on a proposal floated by President Barack Obama in back-to-back State of the Union addresses, isn’t likely to get enacted anytime soon. That’s partly because of its price tag, more $30 billion over the first five years, a tall order in a Congress bent on trimming spending.

On Wednesday, the chairman of the House education committee—Rep. John Kline, R-Minn.—said that Congress must get a handle on the patchwork of existing federal programs before diving into a brand new, pricey initiative. (The bill has been introduced in the House by Rep. George Miller, D-Calif.)

But Harkin, the chairman of the Senate education committee, said at a Thursday hearing that he’s already sure that the current system isn’t cutting the mustard.

“The federal government supports a variety of programs to support early education and care,” he said, including Head Start. “However those investments fall well short of what’s needed.” He cited data from the U.S. Department of Health and Human Services showing that only one in six eligible children get federal assistance. And he dismissed the idea that cost is a barrier. “If you want quality, you have to pay for it.”

But Sen. Lamar Alexander of Tennessee, the top Republican on the panel, likened the Harkin-Miller measure, which would provide matching funds to states to entice them to expand their preschool offerings, to other federal programs that he said have ultimately created a burden at the state level, such as Medicaid.

“Here is what we should not do—that is to fall back into the familiar Washington pattern of noble intentions, a grand promise, lots of federal mandates, and sending the bill to the states with disappointing results,” Alexander said. Instead, he’d like to see Congress fully fund his Head Start “centers of excellence” proposal, which he said would help shine a light on quality programs.

And importantly, Sen. Barbara Mikulski, D-Md., said that while it’s clear the federal government needs a “new commitment” to early learning, she’s not sure that there needs to be a brand new program. (It’s worth noting, however, that Mikulski has signed on as a co-sponsor of the Harkin-Miller bill.)

Instead, Mikuslki would like to see Congress start by taking a close look at existing programs. She gave a shout-out to a bipartisan bill she worked on with Sen. Richard Burr, R-N.C. to reauthorize the Child Care and Development Block Grant program. That measure sailed through the Senate education panel this summer. Plus, Kline had nice things to say about the bill at Wednesday’s House hearing—which means it may have legs. (Harkin told me in an interview after the Thursday Senate hearing that the bill hasn’t yet been scheduled for floor action in the Senate, however.)

Harkin made it clear in the interview that revamping CCDBG, which provides grants to help low-income parents afford child care and after-school programs, isn’t enough on its own to get the needed results on early-childhood education.

“The programs fill different needs,” he said.

So what’s next? While the Harkin-Miller measure may be a legislative long shot—even Deputy Secretary of Education Jim Shelton doesn’t expect it to pass this year—it’s clear that the bill will continue to fuel a broad debate over the right role for the federal government in early learning. Harkin said he’ll be holding another hearing on the measure in April. And he wants the Senate education committee to consider the bill before Memorial Day.

Clearly, the program’s cost is going to be a core part of that debate. The Obama administration proposed paying for a similar initiative by raising taxes on tobacco products, an idea that went over like a lead balloon in Congress. During the Thursday Senate hearing, witnesses were divided on whether more money is necessary.

Danielle Ewen, the director of the office of early childhood education for the District of Columbia, said that high-quality, early-education programs can provide a significant bang for their buck. Washington, she said, recently opened expanded preschool to all 3- and 4-year-olds, regardless of income, and has seen a huge boost in early literacy outcomes for children who participated.

But that’s taken money, she added. “Programs cannot provide high quality if they don’t have the level of resources they need to pay for quality,” Ewen said.

Another witness, Charlotte M. Brantley, the president and CEO of the Clayton Early Learning Program in Denver, agreed. “We have to be honest, for once, about the cost.”

But John White, the Louisiana state chief, noted that federal early-learning programs are fragmented, which he said is at least as big a barrier to making them work well as lack of funding. That was a huge theme in Wednesday’s House GOP hearing.

White would like lawmakers to “take a look at the wide variety of funding streams and allow states greater fungibility of those dollars so that we can actually address questions of classroom quality.” And he added, “If we don’t solve for that fragmentation, we’ll create greater complexity,” which will ultimately lead to “inconsistent student outcomes.”