Congressional candidate Richard Tisei (R) led Rep. John Tierney (D) by 7 points in a recent 6th district poll.

In a confidential polling memo sent from GOP pollster John McLaughlin to Tisei’s campaign manager — and obtained by Roll Call — Tisei took 40 percent to Tierney’s 33 percent, with 27 percent undecided. The horse race numbers include voters who definitely, probably and lean toward voting for each candidate.

Six months before the election, it’s a potentially major development in heavily Democratic Massachusetts, a state that hasn’t elected a Republican to the House since 1994. It’s also likely to be a fundraising boon to Tisei, who has outraised Tierney in each of the past two quarters.

Also in the Republican survey: 36 percent of those surveyed had a favorable opinion of Tierney, while 37 percent had an unfavorable view of the eight-term Congressman. Twenty-two percent had a favorable opinion of Tisei, a former state Senator, while 10 percent had an unfavorable opinion of him. Five percent had never heard of Tierney, while a third of those surveyed had never heard of Tisei.

[scribd id=93583335 key=key-dut0rt8b4azodatvxl0 mode=list]

Tierney has received a slew of bad press this cycle as a result of his wife’s family’s legal troubles.

Within the 6th district, Sen. Scott Brown (R) led presumptive Democratic nominee Elizabeth Warren 57 percent to 33 percent, with 10 percent undecided.

The poll surveyed 400 likely general election voters in the district via live telephone interviews May 2-3. The margin of error was 4.9 points.

A Tierney campaign aide provided numbers from a late January poll that showed Tierney ahead of Tisei by 15 points, 46 percent to 31 percent. That poll, by Democratic pollster Jef Pollock, surveyed 409 voters and had a margin of error of 4.8 points. Roll Call rates this race as Leans Democratic.