Gov. Deval Patrick has widened his lead in the race for the corner office and is now ahead of his closest rival, Republican Charlie Baker, by 13 points, according to the latest Suffolk University/7News poll.

In the poll of registered voters, 42 percent say they would vote for Patrick, compared to 29 percent for Baker and 14 percent for independent Tim Cahill. Green Party candidate Jill Stein gets 8 percent, while 7 percent were undecided. Of the three candidates whose numbers improved since a February 2010 Suffolk University/7News poll, Patrick’s increase of 9 points was higher than Baker’s (+4) and Stein’s (+5). Cahill dropped 9 points, likely due to a $1 million barrage of attack ads financed by the Republican Governor’s Association.

Cahill’s loss is Patrick’s gain

“Tim Cahill’s decline has been a clear net positive for Gov. Patrick,” said David Paleologos, director of the Suffolk University Political Research Center. “Patrick is the better-known alternative, is trusted the most and is perceived to have run the best campaign thus far. More than 60 percent of voters still have no opinion of Charlie Baker or have never heard of him, so he hasn’t given voters a reason to choose him.”

Patrick led among men (39 percent to 30 percent), women (45 percent to 29 percent), white voters (40 percent to 30 percent), minority voters (56 percent to 24 percent) as well as in every region of the state.

Patrick captured 76 percent of registered Democrats, while Baker won 77 percent of registered Republicans. Among independents, Baker led Patrick by 35 percent to 26 percent, far less than the 64 percent to 29 percent advantage among independents that Scott Brown had over Martha Coakley in a Jan. 14 Suffolk University/7 News survey. That survey was the first live telephone poll to show Brown winning.

Opposition to ruling on political funding

As political pundits pore over the impact of the massive media buy against Cahill, voters overwhelmingly opposed the recent Supreme Court ruling that corporations and unions can spend unlimited amounts of money on political advertising.

Eighty-two percent of voters surveyed opposed the ruling, while 14 percent supported it. Seventy-eight percent of voters said it would have a negative effect on elections, while 11 percent said it would have a positive impact.

Managing local aid cuts

When voters were given four possible local actions to make up for projected cuts in local aid, 34 percent said that communities should increase employee contributions to city and town health care plans; 25 percent said that communities should impose a 5 percent salary cut on all city and town employees; 17 percent said that communities should raise property taxes with a Proposition 2½ override; and 6 percent preferred layoffs of selected teachers, police, firefighters and other municipal personnel. Seventeen percent were undecided or had no opinion.

Taking economic temperature

Following a positive report on Massachusetts unemployment rates, 45 percent of voters said the economy is improving, while 49 percent said it is not. Meanwhile, 49 percent of voters said they planned to spend the same as last year on summer vacations, while 27 percent will spend at least 10 percent less, and 13 percent plan to spend at least 10 percent more.

Treasurer’s race

Both Democratic candidates led the Republican nominee for state treasurer, with a significant number undecided. Businessman and party activist Steve Grossman led Republican State Sen. Karyn Polito 37 percent to 28 percent, with 36 percent undecided, and Boston City Councilor Stephen Murphy led Polito 36 percent to 29 percent, with 35 percent undecided.

Tax cuts & casinos

Voters also weighed in on two possible tax-cutting ballot measures. Forty-nine percent of registered voters support an initiative petition to reduce the sales tax from 6.25 percent to 3 percent, while 44 percent oppose it, and 7 percent are undecided. These were the exact same findings as in the February Suffolk University/7 News poll. Voters also supported the elimination of the added sales tax on alcohol by 48 percent to 43 percent, which was slightly closer than the 54-39 margin in February. Casinos in Massachusetts had the support of 55 percent of voters and were opposed by 34 percent, closely tracking the 57-34 margin in February.

Methodology

The statewide survey of 500 Massachusetts registered voters was conducted May 20-23, 2010. The margin of error is +/- 4.4 percent at a 95 percent level of confidence. Some questions have been embargoed until 11 p.m. Wednesday, May 26. Marginals and cross-tabulation data totaling 450 pages will be posted on the Suffolk University Political Research Center Web site. For more information, contact David Paleologos at 781-290-9310.