The seat held by Sen. Scott Brown (R) is supposed to be among Democrats’ best pickup opportunities in 2012. Democrats should be troubled, therefore, by new polling released by the Western New England College Polling Institute.

A whopping 52 percent of voters in the deep-blue Bay State think Brown should be re-elected. And the incumbent Senator, who scored an unlikely victory in the 2010 special election to replace the late Sen. Edward Kennedy (D), is blowing away prospective Democratic challengers in hypothetical matchups.

Brown is popular even among Democrats; 42 percent of Democrats polled March 6-10 approve of Brown’s job performance, compared with 88 percent of Republicans and 64 percent of independents.

“Obviously it’s early in the election cycle and a lot can change in the coming months,” said the polling institute director, Tim Vercellotti. “But the survey results show that the Democrats have a hill to climb to unseat Senator Brown.”

Brown leads potential challenger Rep. Mike Capuano (D) 51 percent to 38 percent. And his lead is larger against Elizabeth Warren, an adviser to President Barack Obama. A handful of other potential Democratic candidates, such as Newton Mayor Setti Warren, who has indicated he’s likely to run for the seat, were not tested in head-to-head matchups.

Western New England College surveyed 472 registered adults and reported a margin of error of at least 4.5 points.