Congressman John Tierney may have reason to smile this week.
A new poll of likely voters published by WBUR shows Tierney, a Democrat from Salem, leading his Republican challenger Richard Tisei of Wakefield.
Both candidates are seeking to represent the Sixth Congressional District, which includes Hamilton and Wenham.
Asked for candidate preference without "leaning" factored in, Tierney leads Tisei by 7 points -- 39 percent to 32 percent -- with 22 percent undecided. Asked the same question with leaning allowed, Tierney's lead over Tisei grows to 12 points -- 46 percent to 34 percent -- with 11 undecided. This suggests about half the undecideds are leaning toward Tierney.
It also suggests Tisei still has work to do if he's going to persuade undecided voters to support him.