The news that Democrat Rep. Tammy Baldwin will run for the open Senate seat in Wisconsin means the ideological division in that state’s race will be epic.

Whether the GOP nominee is former congressman and former gubernatorial candidate Mark Neumann, former governor, senator, and health and human services secretary Tommy Thompson, Wisconsin state assembly speaker Jeff Fitzgerald, or some other new entrant, the Republican option will be either moderately conservative or very conservative.

Tammy Baldwin is, indisputably, one of the most liberal members of Congress. Her lifetime ACU rating is 1.75 out of 100, after 12 years in Congress. I didn’t even know it could go that low.