Through the tall trees of northern Wisconsin, Republican Sean Duffy is stalking a giant. The 38-year-old district attorney is talking fiscal responsibility, job creation, entitlement reform. He’s scoring Washington for higher taxes, and for a health-care takeover. He’s Facebooking and Twittering. He comes across as a serious yet positive reformer, a combo that has caught the public’s eye.

He’ll need that eye, and more, since his Goliath is one David Obey, Democratic head of the Appropriations Committee, the liberal bull who has occupied Wisconsin’s Democratic-leaning 7th congressional seat since before Mr. Duffy was … born. That the Republican is getting some traction says something about how bitter voters are with the Democratic agenda. It says something equally important about a nascent GOP effort to rebrand the party.

I wish I lived in the 7th congressional district of Wisconsin so I could vote for my buddy Sean…