MADISON, Wis. -

A new poll shows Democrat Susan Happ leads Republican Brad Schimel in the race for attorney general, but nearly one-in-four voters are undecided.

The Marquette University Law School poll released Wednesday shows Happ with 40 percent support among registered voters, while Schimel has 33 percent. Twenty-four percent of respondents were undecided or didn't know who they would vote for.

The poll of 815 registered voters was done between Aug. 21 and Sunday. It has a margin of error of plus or minus 3.5 percentage points.

Among likely voters, Happ led Schimel 42 percent to 32 percent with a 4.1 percentage point margin of error.

Happ is the Jefferson County district attorney who won a three-way primary on Aug. 12. Schimel is Waukesha County district attorney and faced no primary challenger.