Lawmakers poised to send new political maps, increasing number of majority-minority districts, to Baker

The Massachusetts Legislature is poised to send to the governor new legislative maps that double the number of Senate districts with majority-minority populations and add 13 more in the House, offering voters the potential to further diversify an overwhelmingly white political body over the next decade.

The Senate on Wednesday approved its newly redrawn map amid small pockets of dissent from Democrats. It then passed a proposed map for the House six days after it overwhelmingly cleared that chamber. The moves set up procedural votes, expected by week’s end, to move the proposals to Governor Charlie Baker’s desk.

The maps, legislative leaders say, reflect last year’s US Census count showing Black, Hispanic, and Asian residents drove the state’s population growth over the last 10 years. In response, the Democrat-dominated Legislature created 33 districts in the 160-seat body where the people of color make up a majority of the population, up from 20. In the Senate, six of 40 districts would be majority-minority instead of the three currently.

“It’s a quality final product,” Senator William N. Brownsberger, a Belmont Democrat who led the process for the Senate, said Wednesday. “We have used every minute we’ve had to keep vetting, to keep adjusting . . . and to respond to input that we’ve received.”

Chelsea and Lawrence, each majority-Latino cities, would gain both House and Senate districts where most people are minorities. The House also added such districts in Framingham, Worcester, Malden, and Brockton, New England’s only majority-Black city.

The House approved its map, 158-1, last week, with Representative Lenny Mirra, a Georgetown Republican, providing the lone dissenting vote. (Mirra later said he believes there’s an “inherent conflict” with sitting politicians drawing their own districts.)

The Senate faced more drama Wednesday in its 36-3 vote. All three dissenting votes came from Democrats, who criticized leaders for not giving them more time to debate the map or what they considered a lack of communication from Brownsberger before their districts changed.

“I am so frustrated that we had conversations, including conversations with the chairman, just a few weeks ago that there would be no change to the district at all,” said Senator Marc R. Pacheco, a Taunton Democrat who voted against the map. “I think we should all take some slight changes in terms of representation if we need to ensure equity and opportunity for all people. I’m just very, very concerned that that didn’t happen here.”

The chamber’s initial proposal had weathered days of criticism — and the prospect of litigation — before leaders released a revised map last week putting Brockton into a newly created majority-minority district, as advocates had lobbied for.

The chamber’s original proposal would have kept Brockton, a 105,000-person city, clustered with several mostly white suburbs that surround it, leaving the seat virtually unchanged from its current iteration, which is represented by Senator Michael D. Brady, a Brockton Democrat. It now would be tied with Avon and parts of Randolph, a 35,000-person community, where like Brockton, roughly 70 percent of the residents are people of color.

The revised Senate map also made small changes to another newly drawn district anchored by Lawrence, adding slightly more of the neighboring Haverhill’s communities of color in an effort to keep neighborhoods whole. But it still split the city between Senate districts, frustrating some elected officials.

Senator Diana DiZoglio, a Methuen Democrat who currently represents Haverhill and voted against the map, said there are districts represented by Senate leadership that saw little to no change. Senate President Karen E. Spilka, for example, would take on no new communities under the plan. Neither would assistant majority leaders Michael J. Barrett and Joan B. Lovely.

Meanwhile, the district of fellow assistant majority leader Sal N. DiDomenico, an Everett Democrat, would undergo major change in shifting to a majority-minority seat.

“This process makes important progress in representation for our communities of color,” DiZoglio said. “But it doesn’t go far enough.”

Senator Barry R. Finegold, an Andover Democrat who currently represents Lawrence but would lose the city under the proposed map, also voted against it.

Brownsberger said the proposal trims the number of split communities from 21 to 11, but he defended the decision to slice Haverhill. “Sometimes communities are glad” to be split and be represented by two senators, he said. “From a community standpoint, it often works out quite well.”

The decennial redistricting process is not done yet. The Legislature’s Joint Committee on Redistricting still has to release new maps for the US House of Representatives, though lawmakers have said they expect the process to be far less controversial than 10 years ago when Massachusetts lost one of its 10 seats because of slow population growth.

The committee is also expected to release newly drawn lines for eight Governor’s Council seats.

History shows that drawing majority-minority districts — particularly when no single ethnic group makes up more than 50 percent of a district’s population — does not always empower communities of color to elect candidates of color, nor does it ensure that the legislative body will grow more diverse.

But advocates emphasize that fair maps are necessary, even if not sufficient, for ensuring communities of color secure political representation and for providing candidates of color the chance to break into an old-school political system where insiders reign and most insiders are white.

Matt Stout can be reached at matt.stout@globe.com. Follow him @mattpstout.