The Democrat vying to succeed retiring Rep. David Obey (D-Wis.) gained a small edge on her Republican rival in fundraising.

State Sen. Julie Lassa (D) raised slightly more than $235,000 between July 1 and Aug. 25, the final reporting period before Wisconsin's Sept. 14 primary. Both candidates face nominal opposition for their nominations but are expected to sail through the vote.

Republican Sean Duffy raised just over $230,000 during the final reporting period, and maintains a cash-on-hand advantage, having slightly less than $700,000 banked for the general, whereas Lassa has some $400,000.

But Lassa has gotten help from the national party. The Democratic Congressional Campaign Committee has already hit Duffy with a TV ad accusing him of wanting to eliminate Social Security.

The Ballot Box considers this open seat race a toss-up.

--Updated at 7:04 p.m.