Before voters get to decide whether to lift the cap on how many charter schools the state allows, lawmakers are taking a crack at their own plan. Initial reaction, however, ranged from mixed to hostile.

Senate President Stan Rosenberg marshaled a group of Democrats to roll out what he considers a comprehensive new plan that would lift the cap on the state's existing 84 charter schools—as long as funding for all public schools also increases.

"We are putting forth legislation today that very importantly, at a bottom line put forth tens of thousands of new seats in innovative classrooms, targeted to districts that are struggling the most," Senate Education Committee Chair Sonia Chang-Diaz, of Jamaica Plain, said at a press conference for the bill Thursday.

Chang-Diaz pointed out a section of the bill that punishes charter operators when their student retention rate drops below that of the local district.

In effect, Chang-Diaz said that the proposed legislation rewards charters that are inclusive and penalizes those that are not.

While lifting the cap as state aid to schools goes up, the bill would also add regulations to make charters operate more transparently, as well as cracking down on oversight on which students, like special needs or English language learners, the charters admit. Funding recommendations in the bill would add $200 million to state education aid for all schools.

But advocates for charters hate the idea and would rather stick to a ballot measure that could appear before voters in November asking to simply lift the cap and allow for 12 more charters a year to open. Great Schools Massachusetts, a coalition of procharter companies and groups, said in a statement that the Senate "turned a blind eye to families desperate for better public schools," and that it "abandons a waitlist of 34,000 students," many who are poor, and who want to attend a charter.

The Pioneer Institute, a think tank with a large intellectual investment in the charter movement, echoed the sentiment: "The Massachusetts Senate’s charter public school bill is disappointing for education reform and the hopes and aspirations of urban school children in the Commonwealth. Unlike the Senate bill that largely became the landmark 1993 Massachusetts Education Reform Act, which had no charter school caps, this Senate bill is intended to stifle the equality of educational opportunity offered by Massachusetts charter public schools, not expand it."

The anticharter school crowd appears to be sour on the bill as well. "The bill would perpetuate the very serious problem inherent in lifting the cap yet again: the expansion of a separate and unequal system," Save Our Public Schools, a group representing teachers unions and parents, wrote in a statement rejecting the Senate's plan.

Gov. Charlie Baker, a charter booster, agrees with the advocates and said Thursday the Senate's plan could hurt taxpayers by requiring more education aid. Because of the tight budget environment, Baker has proposed to spend less on education this year than he promised during his campaign.

The Massachusetts Teachers Association and the Boston Teachers Union did not respond to requests for comment.

Less-sweeping charter legislation came to the floor of the Senate in 2014. Then-Senate President Therese Murray allowed a vote on Chang-Diaz's proposal to lift the cap 1 percent per year without strong-arming senators to support it. The vote failed 26-13, a victory for teachers unions who fought against the cap lift.

It's extremely rare for a piece of major legislation to be put onto the floor of either branch by Democratic leaders without clear confidence that it will pass. In retrospect, the move appears to some observers as a ploy to create the appearance of resonableness where none was intended.

If the charter bill passes the Senate this time, there's still no guarantee that the House will even take up the bill this session before lawmakers recess for the year at the end of July.

Change-Diaz says that this time, the process is different since much of the debate that lead to the 2014 charter bill's failure on the floor has already been discussed and overcome.

"It's a different playing field, right?" Chang-Diaz said. "Senators have sat with this issue for longer, have had more opportunity to voice their reservations and their hopes for what would be included in the bill."

When asked if he is confident that the bill will have the votes to get the bill through the 40-member chamber, Rosenberg said that he will know where senators stand once amendments to the bill are debated.

"I have strong confidence," Rosenberg said. "But I don't have a vote count."