Sen. Norm Coleman (R) continued to hold a significant lead over comedian Al Franken (D) in a poll released last week.

Coleman led Franken, 51 percent to 41 percent, in a statewide survey of 1,572 voters by Quinnipiac University. The survey, taken June 17-24, had a margin of error of 2.5 points.

The survey also asked respondents about the presidential contest, and Gopher State voters said they preferred Sen. Barack Obama (D-Ill.) over Sen. John McCain (R-Ariz.), 54 percent to 37 percent.

Coleman’s lead has widened in recent months, according to public polls from different firms.

While Franken was overwhelmingly given his party’s endorsement at the state Democratic convention earlier this month, his campaign has endured months of bad headlines because of controversies surrounding tax errors and a risqué column he wrote for Playboy magazine in 2000.

Republicans sought to seize on yet another controversy this week involving a joke Franken reportedly made about rape during a 1990s “Saturday Night Live” brainstorming session, as reported by New York magazine. State Rep. Laura Brod (R) delivered a letter signed by Rep. Michele Bachmann (R) to the Democratic Senatorial Campaign Committee asking Chairman Charles Schumer (N.Y.) to condemn Franken’s remarks.

DSCC spokesman Matthew Miller responded to the letter by pointing to recent reports about Coleman’s relationship with a lobbyist friend, who is also his landlord and whose company has been paid by the Senator’s re-election campaign.

“With new reports raising questions about Norm Coleman’s cozy relationship with a major Republican consultant, it’s no wonder his campaign is grasping at straws,” Miller said.