Mayor Martin J. Walsh called Governor Charlie Baker’s proposal to expand charter schools across the state dangerous Tuesday, saying the plan would increase their numbers too quickly, draining district budgets and establishing schools without time for adequate preparation.
“It can set up charter schools for failure . . . if they don’t have the proper boards and facilities,” Walsh told reporters at the State House.
His criticism of Baker’s bill, unveiled last week, marked a split in the usual bipartisan cooperation between the Republican governor and the Democratic mayor, whose positions on charter school expansion had appeared to be in sync.
Baker proposes allowing 12 new or expanded charter schools each year in districts in the bottom 25 percent on standardized tests, such as Boston, New Bedford, Salem, Holyoke, and Lawrence.
The legislation technically leaves in place a statewide cap of 120 charter schools — publicly funded schools that often operate separately from local districts — but would effectively nullify that limit and allow the number to grow each year.
Baker testified before the Legislature’s education committee Tuesday that the dozen schools that could be authorized each year would constitute a mere six-tenths of 1 percent of the state’s 1,900 public schools, but would give hope to thousands of families.
“The time is already long past . . . to address this issue,” he said. “If you enacted this legislation tomorrow, most of the 37,000 children who currently reside on a charter school waiting list could never find their way into a charter school.
“Those parents would probably say — with great force and legitimacy — that this is far too little for them and their kids. And they’d probably be right,” Baker added.
Hundreds packed the State House’s Gardner Auditorium for the hearing, many wearing T-shirts bearing names of charter schools, while some opponents of charter expansion wore stickers reading, “Public Funding. Public Schools.”
In testimony before the committee Tuesday, Walsh laid out a plan that would expand charter schools at a slower pace than in Baker’s proposal. The Walsh proposal would allow the creation of charter school seats in the lowest-performing districts at a rate of half of 1 percent of the local school district budget each year for a decade.
“I know many are calling for the cap to be raised even higher or removed completely,” Walsh said. “I am convinced that such dramatic changes would be reckless under the current funding mechanism and unwise under any circumstances.”
Charter school tuition is drawn from local school district budgets but is partly reimbursed by the state. Walsh proposed a funding system that he said would be less of a drain on district budgets in cities like Boston, which he said has been allotted 36 percent of new charter school seats since 2011 despite having just 7 percent of the state’s total school enrollment.
And he proposed making charter schools eligible for funding from the Massachusetts School Building Authority to help the schools acquire or build proper facilities.
Walsh also asked lawmakers to give school leaders more autonomy in turning around struggling schools and dealing with staffing issues.
While Baker and Walsh both pushed for some level of charter school expansion, many at the hearing vehemently opposed that goal.
Boston City Councilor Tito Jackson offered support for a proposed moratorium on charter school expansion. Jackson cited funding issues, comparable college-entry rates between Boston’s charter schools and district schools, and what he described as excessive use of out-of-school suspensions by charters, particularly for black male students.
“The question here, I believe, is one of equity and one of true opportunity,” Jackson said.
Ruth C. Gilbert-Whitner, superintendent of the Whitman-Hanson Regional School District in Southeastern Massachusetts, said charter schools have siphoned $309,000 from the district’s budget this year, causing drastic cuts in its library services.
“Each and every student in the Commonwealth deserves a high-quality education,” she said, “[not] a dual system of publicly funded education that charges traditional districts for circumstances beyond their control and requires them to operate school systems under a vastly different set of regulations.”
Last year, the House of Representatives passed legislation to raise the charter cap, but a similar bill sank in the Senate.
Senate president Stanley C. Rosenberg told reporters the Senate will decide by Thanksgiving whether to proceed with charter school legislation or leave voters to decide on a proposed ballot measure that would raise the cap.
H e suggested his preference is to develop comprehensive legislation to address not just a potential cap lift, but some of the concerns raised by critics of charter schools. Too often, he said, those concerns are deferred amid periodic moves to raise the cap.
“The conversation is always the same,” he said. “This may be really great for certain places, but it’s causing problems in other places.’’
David Scharfenberg of the Globe staff contributed to this report. Jeremy C. Fox can be reached at email@example.com. Follow him on Twitter @jeremycfox.